These specimens (USNM 113998-114005) are from the marshes along the southeastern shore of Lago de Chapala. Five females have snout-vent lengths of 124.0-138.1 (131.5), and one male has a snout-vent length of 110.2 mm. Two juveniles have snout-vent lengths of 49.7 and 56.3 mm. The coloration of the juveniles is more bold than that of the adults. The body proportions of these specimens agree with those presented by Zweifel (1957:80).

Rana montezumae Baird

This species probably is more abundant and widespread than is indicated by the few specimens listed above. It has been found only in the vicinity of permanent water on the Mexican Plateau and the mountains rising from the plateau at elevations of 1500 to 2000 meters. Its apparent absence from Lago de Pátzcuaro cannot be explained, unless Rana dunni replaces it there.

Rana pipiens Schreber

Except on the Pacific lowlands, this species is abundant throughout the state. It has been collected from sea level to 2800 meters, the greatest altitudinal range of any amphibian in Michoacán. It has been found frequently in the Tepalcatepec Valley; it is not a distinctly highland species in southern Michoacán, as stated by Peters (1954:9). One specimen from Aguililla (UMMZ 119257) is an albino. In this specimen there is a faint pattern on the hind limbs; otherwise the entire body is creamy white; the eyes are pink.

Rana pustulosa Boulenger

Although Rana pustulosa seems to be absent from the Mexican Plateau in Michoacán, it has been collected at elevations of 850 to 2150 meters on the slopes of the Cordillera Volcánico and in the Sierra de Coalcomán. Usually the frogs are found along rocky streams, but at Coalcomán they were found in a hyacinth-choked old river channel, and at El Sabino, in irrigation ditches.

In most specimens the dorsum is dark olive-brown; in some it is pale olive-tan with dense dark brown mottling on the back and dark transverse bands on the hind limbs.

Thirteen tadpoles (UMMZ 94271) taken from a seepage pool by a stream near Uruapan closely resemble the description of tadpoles of this species given by Taylor (1942b).

REPTILIA

Testudines

Chelonia mydas (Linnaeus)

Green sea turtles are abundant along the coast of Michoacán. Laying females and fresh nests were found on August 6-12, 1950, July 14-16, 1951, and July 8-10, 1955. The general account of sea turtles on the coast of Michoacán that was given by Peters (1957) is supplemented here by my field notes on the actions of one female observed on the night of July 14, 1951, near Maruata by Donald D. Brand and I. Because of a full moon, visibility was excellent.

In the course of the day several Chelonia were seen in the surf; shortly after dark the first turtle was observed on the beach. Several were observed to come out on the beach and crawl nearly to the strand line, only to return to the sea.

At 10:20 p. m. one turtle was seen about 15 meters from the water. We watched this turtle from some distance and observed that by 10:26 p. m. she had moved about ten meters to a bank of sand about two meters high. Ten minutes later she had climbed the bank and disappeared over the top into the brush. We moved closer and remained hidden below the bank. Although we could not see the turtle, we could hear her movements. Between 10:37 and 10:57 p. m. the turtle dug, often flipping the dry sand for a distance of about two meters. When this energetic digging ceased, we moved up the bank to see that she was facing inland and sitting in a depression about one and one-half meters in diameter and 30 centimeters in depth. She had cleaned out this depression in the past 20 minutes. Between 11:00 and 11:36 p. m. she dug the nest hole by first scooping sand with one hind flipper and then with the other; when sand was thrown by one flipper, there was a similar, but weaker, motion by the other flipper. At 11:36 p. m. she stopped digging. By crawling up behind the turtle we were able to examine the nest cavity, which measured 21 centimeters across the top and 38 centimeters deep. The diameter of the bottom of the hole was estimated to be about 50 centimeters. At 11:40 p. m. she released the first egg; a minute later she dropped the second. At 11:42 p. m. the third and fourth eggs were released; these were coherent, as were the fifth and sixth eggs released at 11:43 p. m. After this, as many as three eggs were dropped at a time. After laying about 60 eggs, she paused for a minute and then continued laying. By 11:55 p. m. she had laid 98 eggs; after this, the process of deposition slowed considerably. She dropped a fragment of an egg followed by normal eggs. At midnight she deposited a miniature egg about 20 mm. in diameter. This terminated the deposition. Immediately she began to cover the nest.

Within ten minutes after the last egg was deposited the nest had been covered. The turtle first had been seen at 10:20 p. m.; judging from its speed and its distance from the water, the turtle probably had been on land for about ten minutes. About 25 minutes were used in crawling from the water to the nesting site. One hour and 33 minutes were spent at the nesting site; of this time twenty minutes were taken for egg deposition. The turtle was not followed back to the water, but if the return trip took approximately the same amount of time as required to travel from the ocean to the nesting site, the total elapsed time from departure to return to the water was about two and one-half hours.

We collected the eggs as they were deposited. There were 106 eggs, each having a diameter of about 40 mm., plus one small egg and a fragment of another. The turtle had a carapace about one meter in length.

From our limited observations of sea turtles and their tracks on the beaches, and from the accounts of these animals by the residents of the coastal region, great numbers of sea turtles use these relatively uninhabited beaches for nesting grounds. However, the turtles do not go unmolested. The natives capture turtles and collect their eggs. Opened and emptied nests also showed signs of predatory activity on the part of other mammals. In the vicinity of Playa Azul several turtles were killed by dogs.

Kinosternon hirtipes hirtipes Wagler

One specimen from eight kilometers west of Ciudad Hidalgo (UIMNH 24707) is from the Río Tuxpan, a tributary of the Río Balsas; this is the only record for the species from the Balsas drainage. All others are from the lakes or rivers flowing into the lakes on the southern part of the Mexican Plateau. This species exists in Lago de Pátzcuaro to the apparent exclusion of the abundant and widespread Kinosternon integrum.

Kinosternon integrum LeConte

Excepting Lago de Pátzcuaro, Kinosternon integrum occupies all permanent and temporary ponds, lakes, and streams below 2200 meters throughout the state. At Coalcomán the species was in roadside ditches, small puddles, flooded fields, a hyacinth-choked ox-bow of the Río Coalcomán, as well as in the Río Coalcomán and its tributaries. Specimens from Arteaga and Barranca de Herradero were found in clear rocky streams; the one from Las Higuertas was found in a small muddy pond in pine-oak forest.

On August 26, 1960, James R. Dixon found a copulating pair in a pool at Capirio. The large series from Coalcomán contains juveniles and adults; these turtles formed the basis for the study of relative growth of plastral scutes in this species by Mosimann (1956).

Geoemyda rubida perixantha Mosimann and Rabb

These specimens have been discussed in detail by Mosimann and Rabb (1953). All are from the arid tropical scrub forest; those from the coastal regions were collected at elevations of less than 40 meters, and those from the Tepalcatepec Valley were collected at an elevation of 335 meters.

Crocodilia

Crocodylus acutus acutus Cuvier

The crocodile or "caiman" is abundant in the brackish lagoons along the cost of Michoacán; three large adults and several juveniles were observed at Estero Pichi at Playa Azul; others were seen at Mexiquillo and Maruata. Residents of the Balsas-Tepalcatepec Basin frequently have reported "caimanes" in the Río Balsas and Río Tepalcatepec, but the existence of the crocodile in these rivers has not been verified by specimens.

Sauria

Phyllodactylus duellmani Dixon

This species is known only from the Tepalcatepec Valley, where it has been found in open arid situations from 180 to 500 meters. Specimens were found in the daytime in stumps, dead cacti, and the hollow branches of the legume, Apoplanesia paniculata. In life adults were pale gray or grayish tan above and creamy white below. A juvenile having a snout-vent length of 18 mm. had a pale orange tail with gray cross-bands. In the adults the tail was colored like the body. The specimen from 14 kilometers south-southwest of Apatzingán (KU 29764) and those from Cofradía (BMNH 1914.1.28.28-30) were not listed by Dixon (1960).

Phyllodactylus homolepidurus Smith

These specimens have been referred to Phyllodactylus homolepidurus by James R. Dixon (in litt.), who is currently studying the American members of the genus. Geckos of this species have been found in tropical semi-deciduous forest in the coastal lowlands to elevations of 500 meters. Most specimens were found beneath the bark of standing dead trees or stumps. Two individuals from El Ticuiz (UMMZ 115102) in life were dark gray above with brownish tubercles; the belly was a dusty cream-color. Apparently this species does not enter the Tepalcatepec Valley, where Phyllodactylus lanei is abundant.

Phyllodactylus lanei Smith

This widespread species has been taken at elevations of less than 1100 meters in the Balsas-Tepalcatepec Basin, where it occurs in riparian situations in the foothills. Specimens have been collected in tropical semi-deciduous forest at Ostula and in oak forest south of Arteaga; both of these localities are on the Pacific slopes of the Sierra de Coalcomán, a region inhabited by Phyllodactylus homolepidurus. Both species have been collected at Ostula.

A juvenile from 21 kilometers south of Arteaga (UMMZ 118933) had alternating black and white bands on the tail. In life most of the lizards are dull ashy gray or grayish tan above and white below. According to Dixon (in litt.), one specimen from Apatzingán (UMMZ 115102) resembles Phyllodactylus magnus in scutellation, but it lacks the distinctive yellow venter of that species.

Apparently Phyllodactylus lanei is restricted to rather mesic environments in the Balsas-Tepalcatepec Valley and surrounding foothills; in the more open arid environments on the floor of the valley it seems to be replaced by Phyllodactylus duellmani.

Phyllodactylus paucituberculatus Dixon

Two of these specimens (UMMZ 112692-3) were discussed in detail by Dixon (1960:40) in his description of the species. On August 25, 1960, Dixon collected four additional specimens at the type locality, a conglomerate cliff along the Río Marquez. These will be reported by him in his forthcoming study of the genus.

Anolis dunni Smith

Three females from Arteaga (UMMZ 119075) have snout-vent lengths of 41, 41, and 44 mm. In life the pale grayish brown dorsum was marked with dark brown; the belly was white, and the throat was pale pink. All have a dark interorbital bar and dark vertical bars on the upper labials. In two specimens there are only scattered dark flecks on the dorsum; in the third there is a dark postorbital stripe, a dark lateral stripe, and four narrow transverse bands on the body. A male from 19 kilometers south of Arteaga (UMMZ 119076) having a snout-vent length of 49 mm. had in life a tan dorsum, a broad white stripe from the ear to the groin, scattered small white spots on the dorsum, and indistinct pale cream-colored spots on the posterior surfaces of the thighs. This male has the dark labial bars, but lacks the dark interorbital bar, found in the females. The large rose-pink throat fan extends to about the middle of the belly. In all of the specimens the middorsal scales are keeled and much smaller than the smooth pavementlike or slightly imbricate ventrals. All have two gulars in contact with the mental, five scales between the nasals, five scales (not including the first labials) in contact with the rostral, and four rows of loreals. In these characters these specimens agree well with Anolis dunni from Guerrero, as diagnosed by Davis (1954b).

Previously Anolis dunni has been reported only from the vicinity of Agua del Obispo, Guerrero, a locality situated at an elevation of about 900 meters in pine-oak forest in the Sierra del Sur. All known close relatives of Anolis dunni occur only in Guerrero: A. taylori Smith and Spieler from Acapulco, A. gadowi Boulenger from Tierra Colorado, A. liogaster Boulenger, and A. omiltemanus Davis from Omiltemi. The present specimens from elevations of about 900 meters in riparian stream vegetation and oak forest represent the northern known limits of this group of Anolis.

Anolis nebulosus (Wiegmann)

Even with the abundance of material the assignment of a specific name to these anoles is only tentative, for definite determination between Anolis nebulosus Wiegmann and A. nebuloides Bocourt is uncertain. Bocourt (1873:75) distinguished A. nebuloides from A. nebulosus by the following characters: (1) head scales keeled, not smooth; (2) snout narrower; (3) ear opening larger; (4) supraorbital semicircles separated by a row of small scales and not in contact; (5) dorsal scales larger and subequal in size to the belly scales. Boulenger (1885:77) used the same characters; Smith and Taylor (1950b:58) in their key to the Mexican species of Anolis stated that the dorsal scales are slightly smaller than the ventrals in A. nebulosus and markedly smaller in A. nebuloides. Smith (in litt.) stated that the characters of the relative sizes of the dorsal and ventral scales were incorrect in that key.

The application of the above criteria to specimens from Michoacán has not resulted in the recognition of two species. The majority of the specimens have the supraorbital semicircles separated by at least one small scale; the head scales, with the exception of those on the snout in a few individuals, are smooth; the dorsal scales are only slightly smaller than the ventrals. In other characters of scutellation the specimens are highly variable. The males in life have an orange throat fan. Anoles of this kind have been found in Michoacán, Colima, Jalisco, Nayarit, and southern Sinaloa. Near Oaxaca, Oaxaca, specimens were collected that superficially resemble those from Michoacán and farther north. These have low keels on the snout scales, dorsals somewhat larger than the ventrals, and a pink throat fan. In ten males from Oaxaca the size of the dorsal scales relative to that of the ventrals is 1.00:0.83; the same ratio for 25 males from Michoacán is 1.00:1.08. In both samples there are specimens in which the dorsal and ventral scales are about equal in size.

Investigations by Richard E. Etheridge on the osteology of Anolis, including those species here being considered, have revealed relatively constant differences in the parasternalia and in the caudal vertebrae. The application of Etheridge's findings to anoline systematics must await the completion of his study.

The carination of the scales on the snout versus smooth scales there seems to be the only significant character given by Bocourt that distinguishes A. Nebuloides from A. nebulosus. The difference in the color of the throat fan, which is apparent only in living individuals, is more striking. Obviously more than one species is represented, as is borne out by the differences in the color of the throat fan and in the osteology, but there is uncertainty about the correct name for each species. On the strength of Bocourt's diagnosis of keeled snout scales in A. nebuloides, I am applying that name to the population in Oaxaca and A. nebulosus to the specimens from Michoacán. As arranged here, the two species can be distinguished, as follows:

With respect to geographic distribution, A. nebulosus has been collected from southern Sinaloa southward to Michoacán. The lizards here referred to A. nebuloides have been taken only in pine-oak forest on the mountain slopes near Oaxaca City. Zweifel and Norris (1955:233) reported anoles with pink throat-fans from southern Sonora; possibly those specimens are A. nebuloides; I have not examined them. I have seen several preserved specimens from the vicinity of Tehuantepec, Oaxaca. Although they probably belong to this group, those specimens differ from both A. nebulosus and A. nebuloides in their larger size, relatively larger head, and much larger throat fan.

Aside from the minor variation in scutellation, specimens of Anolis nebulosus from Michoacán vary greatly in coloration. Usually the females have some form of a broad middorsal pale-colored band. In life this is dull yellow, tan, or orange. Two females from Dos Aguas are strikingly different; one (UMMZ 119521) has a broad middorsal orange stripe that is scalloped laterally and bordered by gray. The other (UMMZ 119081) has a narrow middorsal cream-colored line. Males usually are unicolor brown or olive-tan; sometimes the middorsal region is darker. Some individuals have dark cross-bands or chevrons on the dorsum. One male from Dos Aguas (UMMZ 119080) has a cream-colored lateral stripe.

In Michoacán Anolis nebulosus occurs from sea level to elevations slightly in excess of 2100 meters, usually in areas of dense cover, whether this be herbaceous, viney, or woody, ordinarily on the ground as well as in bushes and trees. One was in a bromeliad growing about ten meters above the ground. In the arid Tepalcatepec Valley anoles of this species are most frequently found in the tangled growth along streams. Above Uruapan they were found in pine-oak forest, and on the Mexican Plateau between Zamora and Zacapu they were found in a bunch grass-scrub oak association.

Anolis schmidti Smith

Peters (1954:11) reported on the specimen from La Placita; another was secured at San Juan de Lima in 1956. The latter (UMMZ 115078) is a male having a snout-vent length of 43.0 mm. and a tail length of 70.5 mm. The dorsal ground color is pale tan; there are five pairs of irregular dark brown dorsolateral blotches. In life the throat fan was pale orange. These specimens agree with those from Colima described by Duellman (1958c:10). The distribution of Anolis schmidti seems to be restricted to the coastal lowlands from Michoacán to Nayarit.

Basiliscus vittatus Wiegmann

This species has been found only on the coast and in the low Tepalcatepec Valley. In the latter area it is restricted to riparian situations along the larger streams. The lizard is abundant in the mangrove swamps bordering the brackish lagoons on the coast. In July, 1955, scores of individuals were seen around Estero Pichi at Playa Azul. Adults, especially the large males, are exceedingly wary and difficult to collect. At all localities where they were found, the lizards were most often seen in dense bushes, where they are well camouflaged. Individuals of all sizes were observed to run across the surface of the ponds.

Iguana iguana rhinolopha Wiegmann

Like the preceding species, this lizard is always found near water. It does not ascend the foothills of the Sierra de Coalcomán, but in the Balsas Basin it reaches elevations of 800 meters at La Playa. Large adults are often seen in the large trees making up the gallery forests along rivers. From high perches the lizards drop into the water with a terrific splash. Bright green juveniles were abundant in bushes along the Río Tepalcatepec in July, 1955.

Ctenosaura pectinata (Wiegmann)

Ctenosaura pectinata is a common lowland species that ascends the slopes of the Sierra de Coalcomán and the Cordillera Volcánica to elevations of about 1050 meters (approximating the lower limits of the oak forest). The record from Uruapan (USNM 10234, collected by Dugès) is doubtful.

These large lizards are most easily observed on rock fences along roads. Near Apatzingán innumerable individuals can be seen in mid-morning. Later in the day, as the sun rises higher in the sky, the lizards retreat to the shade of the crevices in the fences. The abundance of these lizards in the Tepalcatepec Valley, together with evidence gathered from the natives of the valley, indicates that these lizards are seldom used for human consumption there. On the other hand, several people in Coalcomán consider the "iguana negra" (local name for Ctenosaura) to be a delicacy and serve it at every opportunity. In early July, 1951, brilliant green young of the year were collected at La Playa and at Coalcomán.

Enyaliosaurus clarki (Bailey)

This species is known only from the low areas of the Balsas-Tepalcatepec Basin between elevations of 200 and 510 meters. It is commonly found in the open arid tropical scrub forest dominated by Prosopsis sp., Apoplanesia paniculata, and Cercidium plurifoliolatum. Continued collecting in the Tepalcatepec Valley has borne out the suggestions of Duellman and Duellman (1959) concerning the distribution and abundance of this lizard. Also, continued collecting in Colima and on the Pacific coast has failed to reveal the presence of Enyaliosaurus there.

Phrynosoma asio Cope

In Michoacán this species has been obtained only in the Tepalcatepec Valley and on the northern slopes of the Sierra de Coalcomán between 300 and 700 meters. Apparently the lizard is absent from the coastal lowlands of Michoacán and Guerrero. The distribution of this species, therefore, is discontinuous. One population inhabits the lowlands of Colima and the Balsas-Tepalcatepec Basin inland to northern Guerrero and Morelos; a southern population inhabits the Plains of Tehuantepec in Oaxaca.

A juvenile from Apatzingán (USNM 47739) has a snout-vent length of 40.0 mm. and a tail length of 19.5 mm.

Sceloporus aeneus aeneus Wiegmann

This small terrestrial species inhabits the pine and fir forests of the Cordillera Volcánica between elevations of 1850 and 3100 meters; apparently it is absent from the Sierra de Coalcomán. It seems to prefer rather open coniferous forests in which there is a more or less continuous cover of grasses on the ground. On warm sunny days the lizards can be observed scurrying about in the grass; in the early hours of the day, or on cold days, they are found beneath stones, logs, or dead clumps of bunch grass.

Sceloporus asper Boulenger

This strictly arboreal lizard is abundant in the mixed broad-leafed forest near Uruapan. The lizards are exceedingly wary and can be approached only with difficulty. In life males have pale blue bellies; the throat is pale pink. The pale gray dorsum marked with irregular darker gray blotches blends well with the color of the tree trunks on which the lizard lives. The one specimen from Dos Aguas was found on a pine tree; it provides the only record for the species from the Sierra de Coalcomán.

Sceloporus bulleri Boulenger

Heretofore this species has been known only from a few specimens from scattered localities in the Sierra Madre Occidental in southwestern Jalisco and Sinaloa. The collection of a large series of these lizards in virgin pine forest at elevations of more than 2000 meters in the Sierra de Coalcomán now makes possible an analysis of variation in the species.

Superficially S. bulleri resembles S. torquatus, but S. bulleri is smaller, has more dorsal scales, fewer scales in the dark collar, and fewer femoral pores. In 88 specimens of S. bulleri there are 36-41 (38.7) dorsal scales and 2 or 3 (2.6) middorsal scales in the collar, as compared with 28-31 (29.3) dorsal scales and 3 or 4 (3.4) middorsal scales in the collar of 26 specimens of S. torquatus from Uruapan. In 20 adult males of S. bulleri there are 13-15 (14.3) femoral pores, and 13-16 (14.4) in 11 females; 13 males of S. torquatus have 14-21 (17.3) femoral pores, and 13 females have 15-21 (16.7). Seventeen adult males of S. bulleri have snout-vent lengths of 72-91 (82.0); ten females, 71-87 (75.7). In comparison, 13 adult males of S. torquatus have an average snout-vent length of 88.9 mm., and 13 females, 88.5 mm. In S. bulleri there is little variation in the head scales. The frontal is in contact with the interparietal in 63, and not in 24, specimens; the median frontonasal is in contact with the frontal in 13, and not in 74, specimens. In 39 specimens there are two canthals, and in 48 there is one; in 29 specimens there are three preauriculars, and in 58 there are four.

In life adult males have a pale blue tail, bright blue belly patches, a purplish blue throat, and pale blue lines on the sides of the head and neck.

This species was obtained at four localities in the high mountains of the Sierra de Coalcomán. In this mountain range Sceloporus bulleri apparently replaces S. torquatus, a species that is widespread in the Cordillera Volcánica and on the Mexican Plateau. At Dos Aguas and at Acuaro de las Lleguas the lizards were abundant in the tall pine forest, where they were found on standing pine trees, on pine logs, and on rock outcroppings.

Sceloporus dugesi intermedius Dugès

This lizard is strictly an inhabitant of the Mexican Plateau, where it is found in rocky places, sometimes in pine-oak forest, but more frequently in mesquite-grassland. It is a terrestrial species, and is most often seen on rock fences at elevations of 1500 to 2200 meters.

This species differs from S. bulleri and S. torquatus in having two rows of supraoculars, instead of one; also it has more dorsal scales. Twenty-six specimens of Sceloporus dugesi intermedius from Tangamandapio and Tangancícuaro have 44-48 (45.7) dorsal scales, as compared with an average of 38.7 in S. bulleri and 29.3 in S. torquatus. In life Sceloporus dugesi intermedius has a dull greenish gray dorsum; in males the belly patches are bright blue bordered medially by black, and the throat is bluish gray. The largest specimen examined is a male having a snout-vent length of 80 mm.

Sceloporus gadowae Boulenger

Although this species has a rather extensive range in the Balsas-Tepalcatepec Basin in the state of Michoacán, Guerrero, Morelos, and Puebla, it is only locally abundant in that area. Usually these lizards are found on rocky cliffs in which there are many crevices for cover. Sceloporus gadowae is abundant on a conglomerate cliff along the Río Marquez south of Lombardia. Although the closely related S. pyrocephalus is abundant in the stream valley and in the hills above the cliff, S. gadowae has been found only on the cliff; few individuals of S. pyrocephalus have been observed on the cliff. A similar situation was discovered on a much more extensive conglomerate cliff along the Río Balsas near Mexcala, Guerrero. Near Tehuitzingo, Puebla, where S. pyrocephalus was not found, S. gadowae was found on conglomerate cliffs. Probably there is strong competition between the two species; possibly this has resulted in the restriction of S. gadowae to isolated cliff-habitats within the extensive range of the more widespread S. pyrocephalus.

In Michoacán Sceloporus gadowae has been found along the lower slopes of the Cordillera Volcánica at elevations from 250 to 1050 meters. All of the localities from which this lizard is known lie in the arid tropical scrub forest.

Sceloporus grammicus microlepidotus Wiegmann

This small species of Sceloporus is an ubiquitous inhabitant of the coniferous forests from 1550 to 3100 meters in the Cordillera Volcánica. Usually it is seen on tree trunks, but occasionally on the ground. Near the lower limit of the altitudinal distribution of the species, as at Uruapan, individuals sometimes are found on broad-leafed trees. Apparently Sceloporus heterolepis replaces S. grammicus microlepidotus in the Sierra de Coalcomán.

Sceloporus heterolepis Boulenger

Although Michoacán has not previously been included in the range of this lizard, it was first collected in the state by Gadow in 1908 (BMNH 1914.1.28.69 from Araparicuaro). The description of S. heterolepis given by Smith (1939:197) can be supplemented by data on the 23 specimens now in the collections of the Museum of Zoology at the University of Michigan. All have two canthals; there are 55 to 71 (63.6) scales in the middorsal row; 1 to 3 rows middorsally are somewhat enlarged and bordered on either side by a row of larger scales bearing high keels. There are 14 to 20 (16.2) femoral pores. Eight adult males have snout-vent lengths from 49 to 61 (58.0) mm. and tail lengths from 57 to 74 (66.0) mm.; four adult females have snout-vent lengths from 52 to 57 (55.2) mm. and tail lengths from 60 to 66 (63.5) mm. The smallest of eight juveniles has a snout-vent length of 28 mm. and a tail length of 32 mm. The dorsum in adults is pale grayish brown; there are three irregular chevron-shaped dark marks and a triangular dark brown mark above the insertion of the hind limbs; on the tail are dark brown rings. There are scattered faint blue flecks on the flanks and narrow transverse dark lines on the lower limbs. Males have pale bluish green belly patches and an orange-salmon-colored throat; the belly in females is pale orange-tan. The juveniles have a more contrasting color pattern; the dark chevrons on the dorsum are bordered posteriorly by pale gray.

In Michoacán this species has been obtained in pine and pine-fir forests from 1800 to 2700 meters. On Cerro Barolosa and at Dos Aguas, both in the Sierra de Coalcomán, the lizards were found beneath the bark of dead, standing pines. In the Sierra de Coalcomán Sceloporus heterolepis seems to fill the niche of the small arboreal Sceloporus in the coniferous forest in southwestern México, a position held by S. grammicus microlepidotus in the Cordillera Volcánica; the latter species does not occur in the Sierra de Coalcomán. Five specimens of Sceloporus heterolepis are known from the Cordillera Volcánica, whereas 603 of S. grammicus microlepidotus have been collected there. The ecological relationships that exist between the two species in the Cordillera Volcánica are not known.

Insofar as is known, Sceloporus heterolepis reaches the southern limits of its range in the Sierra de Coalcomán and in the western part of the Cordillera Volcánica. Other records for the species are from the Sierra Madre Occidental in Jalisco. Langebartel (1959) described Sceloporus shannonorum from the mountains near the Durango-Sinaloa border; the single specimen of S. shannonorum differs significantly from S. heterolepis only in having fewer dorsal scales (48). The acquisition of additional material, especially from Nayarit and northern Jalisco, probably will provide a basis for showing that these two populations are conspecific.

Sceloporus horridus oligoporus Cope

All of the specimens from Michoacán seem to be typical S. horridus oligoporus; none has more than six femoral pores.

Characteristically this species is found in open arid scrub forest; it reaches its greatest abundance in rocky areas in which there are scattered leguminous trees and bushes. It has been found in these low trees and bushes almost as frequently as it has been found on the ground; none has been seen in large trees or far above the ground. Altitudinally, this species ranges from sea level to about 1600 meters.

Sceloporus melanorhinus calligaster Smith