In the second or Glossophagine division of the subfamily the muzzle is long and narrow; the tongue remarkably long and extensible, much attenuated towards the tip, and beset with very long filiform recurved papillæ; lower lip with a wide groove above, and in front margined by small warts; nose-leaf small; tail short or absent. Dentition: i ¹⁄₁, c ²⁄₂, p ²⁻³⁄₃₋₂, m ²⁄₃₋₂; teeth very narrow; molars with narrow W-shaped cusps, sometimes indistinct or absent; lower incisors very small or deciduous.

The ten species included in this division are arranged under seven genera,[636] distinguished principally by differences in the form and number of the teeth and the presence or absence of the zygomatic arch. The form and position of the upper incisors are extremely variable. In Glossophaga and Phyllonycteris the upper incisors form, as in the Vampyrine division, a continuous row between the canines; in Monophylla and Leptonycteris[637] they are separated into pairs by a narrow interval in front; while in Lonchoglossa, Glossonycteris, and Chœronycteris they are widely separated and placed in pairs near the canines. In the first four genera the lower incisors are present (at least up to a certain age), while in the last three they are deciduous even in youth. The zygomatic arch is wanting in Phyllonycteris, Glossonycteris, and Chœronycteris.

The typical species is Glossophaga soricina, which so closely resembles Hemiderma brevicauda, both in external form and dentition, that it has frequently been confounded with it. Its long fimbriated tongue, which it possesses in common with other species of the division, led Spix to describe it as a blood-sucker, believing that this organ was used to increase the flow of blood. This view is, however, without foundation, and from later observations it is evident that the peculiarly shaped tongue is used by the animal to lick out the pulpy contents of fruits having hard rinds. The food of the species of this division appears to consist of both fruit and insects, and the long tongue may also be used for extracting the latter from the deep corollæ of certain flowers. This type of tongue is shown in the woodcut of the head of Chœronycteris (Fig. 320); and it is paralleled among the Megachiroptera by the Carponycteriine Pteropodidæ.

The Stenodermatine division is characterised by the muzzle being very short and generally broad in front, the distance between the eyes nearly always exceeding (rarely equal to) that from the eye to the extremity of the muzzle; nose-leaf short, horse-shoe shaped in front, lanceolate behind (except in Brachyphylla and Centurio); interfemoral membrane always concave behind; tail none; inner margin of the lips fringed with conical papillæ. Dentition: i ²⁄₂₋₁, p ²⁄₂, m ³⁻²⁄₃₋₂; the number of the molars being either ³⁄₃, ²⁄₃, or ²⁄₂ in different species; premolars and molars very broad (except in Sturnira), the latter with concave or flat crowns margined externally by raised cutting-edges. Although the members of this division are usually distinguished from those of the Vampirine division by the peculiar shortness and breadth of the muzzle and the form of the molars, yet certain species of the latter closely resemble those of the former in external appearance, agreeing almost absolutely in the form of the nose-leaf, of the ears and tragus, and of the warts on the chin. These resemblances indicate that, while the form of the teeth and jaws has become modified to suit the nature of the food, the external characters, being but slightly affected by this cause, have remained much the same. The food of these Bats appears to be wholly or in great part fruit. The twenty species have been grouped into nine genera, distinguished by the form of the skull and teeth. Artibeus, with six species, includes the well-known frugivorous Bat, A. perspicillatus. Waterton believed that A. planirostris, a common Bat in British Guiana, usually found in the roofs of houses, and now known to be frugivorous, was the true blood-sucking Vampire. Stenoderma achradophilum, found in Jamaica and Cuba, associated with Artibeus perspicillatus, from which it is scarcely distinguishable externally except by its much smaller size, differs altogether in the absence of the horizontal plate of the palatal bones. Sturnira lilium, while agreeing with the above in the form of the nose-leaf and ears, differs from all the species of the family in its longitudinally-grooved molars, which resemble those of the Pteropodidæ more closely than those of any other Bats; and the presence of tufts of long differently coloured hairs over glands in the sides of the neck shows another common character still more remarkable, which can scarcely be considered the result of adaptive change. Centurio senex is the type of a genus distinguished from Stenoderma and other genera of this division by the absence of a distinct nose-leaf; its facial aspect, as shown in Fig. 321, is altogether bizarre.

In the last or Desmodont division the muzzle is conical and short; there is a distinct nose-leaf; the interfemoral membrane is very short; and the tail is wanting. Dentition: i ¹⁄₂, c ¹⁄₁, p ²⁄₃, m ¹⁻⁰⁄₁₋₀; total 24 or 20. Upper incisors very large, trenchant, occupying the whole space between the canines; premolars very narrow, with sharp-edged longitudinal crowns; molars rudimentary or wanting; stomach greatly elongated, intestiniform. There are only two genera, the single species of each of which are the true blood-sucking Vampires. They appear to be confined chiefly to the forest-clad parts, and their attacks on men and other warm-blooded animals were noticed by some of the earliest writers. Thus Peter Martyr (Anghiera), who wrote soon after the conquest of South America, says that in the Isthmus of Darien there were Bats which sucked the blood of men and cattle when asleep to such a degree as to kill them. Condamine, a writer of the eighteenth century, remarks that at Borja (Ecuador) and in other places they had entirely destroyed the cattle introduced by the missionaries. Sir Schomburgk relates that at Wicki, on the river Berbice, no fowls could be kept on account of the ravages of these creatures, which attacked their combs, causing them to appear white from loss of blood. Although these Bats were known thus early to Europeans, the species to which they belonged were not determined until about sixty years ago, several of the large frugivorous species having been wrongly set down as blood-suckers and named accordingly; and it fell to the lot of Darwin to determine at least one of the blood-sucking species, the following being his account of the circumstances under which the discovery of the sanguivorous habits of Desmodus rufus was made: “The Vampire Bat is often the cause of much trouble by biting the horses on their withers. The injury is generally not so much owing to the loss of blood as to the inflammation which the pressure of the saddle afterwards produces. The whole circumstance has lately been doubted in England; I was therefore fortunate in being present when one was actually caught on a horse’s back. We were bivouacking late one evening near Coquimbo, in Chili, when my servant, noticing that one of the horses was very restive, went to see what was the matter, and, fancying he could detect something, suddenly put his hand on the beast’s withers and secured the Vampire.”

These Bats present, in the extraordinary differentiation of the manducatory and digestive apparatus, a departure from the type of other members of the family unparalleled in any of the other orders of Mammalia, standing apart from all other mammals as being fitted only for a diet of blood, and capable of sustaining life upon that alone. Travellers describe the wounds inflicted by the large sharp-edged incisors as similar to those caused by a razor when shaving: a portion of the skin being shaved off and a large number of severed capillary vessels thus exposed, from which a constant flow of blood is maintained. From this source the blood is drawn through the exceedingly narrow gullet—too narrow for anything solid to pass—into the intestine-like stomach, whence it is probably gradually drawn off during the slow process of digestion, while the animal, sated with food, is hanging in a state of torpidity from the roof of a cave or the inner side of a hollow tree.

Desmodus.[638]—No true molar, and no calcar. The Common Vampire (D. rufus) is widely spread over the tropical and subtropical parts of Central and South America from Oaxaca to Southern Brazil and Chili. It is a comparatively small species, a little larger than the common Noctule, the head and body being about 3 inches in length, the forearm 2½, with a remarkably long and strong thumb; it is destitute of a tail, and has a peculiar physiognomy, well represented in Fig. 322. The body is covered with rather short fur of a reddish-brown colour, but varying in shade; the extremities of the hairs being sometimes ashy. The teeth are peculiar and admirably adapted for the purposes for which they are employed. The upper incisor is greatly enlarged, and of somewhat triangular shape (Fig. 323); the canine, although smaller than the incisor, is large and sharp; but the cheek-teeth are very small, with laterally compressed crowns rising but slightly above the level of the gum, their longitudinally disposed cutting-edges being continuous with the base of the canine and with each other. The lower incisors are small, bifid, and separated from the canine, with a space in front. The lower cheek-teeth are narrow, like those in the upper jaw, but the anterior tooth is slightly larger than the others, and separated by a small space from the canine. Behind the lower incisors the jaw is deeply hollowed out to receive the extremities of the large upper incisors. The exceedingly narrow œsophagus opens at right angles into the slender, intestine-like stomach, which almost immediately terminates on the right, without a distinct pylorus, in the duodenum, but on the left forms a greatly elongated fundus, bent and folded upon itself, appearing at first sight like part of the intestines. This cardiac extremity of the stomach is, for a short distance, to the left of the entrance of the œsophagus, still very narrow, but soon increases in size, till near its termination it attains a diameter quite three times that of the short pyloric portion. The length of this cardiac diverticulum of the stomach appears to vary from 2 to 6 inches, the size in each specimen probably depending on the amount of food obtained by the animal before it was captured.

Diphylla.[639]—A small true molar in each jaw, and a rudimentary calcar. The single species D. ecaudata inhabits Brazil, and appears to be much less abundant than Desmodus rufus, from which, in addition to the characters already mentioned, it is distinguished by its slightly smaller size, the absence of a groove in the front of the lower lip, the non-development of the interfemoral membrane in the centre, and the peculiar form of the lower incisors, which are much expanded in the direction of the jaws and pectinated, forming a semicircular row touching each other, the outer pair being wider than the inner ones, and having six notches, the inner pair having only three notches.

Fossil Phyllostomatidæ.—Remains of Vampyrus spectrum, as well as of several species of Phyllostoma or closely allied types, are found in the cavern deposits of Brazil. The mandible of a large Bat from the Upper Eocene Phosphorites of Central France, described as Necromantis, has been referred to this family—a determination which, if confirmed, will be of great interest from a distributional point of view.