Definition.—Aulosphærida with triangular meshes in the network, the tangential tubes of which form a simple smooth lattice-sphere. No radial tubes at the nodal points.
The genus Aularia is the simplest form of the subfamily Aularida, or of those Aulosphærida in which the network of the shell is composed of regular or subregular triangular meshes; they are the main group of the family, much more common and far richer in distinct forms than the Aulonida (or the Aulosphærida with polygonal meshes). The shell of Aularia, the probable ancestral form of the family, is a simple lattice-sphere with smooth surface, and differs from the common Aulosphæra in the absence of radial tubes, arising at the nodal points.
1. Aularia ternaria, n. sp. (Pl. 111, fig. 2).
Tangential tubes of the network cylindrical, straight, smooth, of equal breadth. Triangular meshes of the reticular sphere very regular, equilateral triangular. This species is the simplest of all Aulosphærida and similar to the common Aulosphæra trigonopa, but has no radial tubes.
Dimensions.—Diameter of the sphere 1.0 to 2.0; tubes 0.1 to 0.15 long, 0.007 to 0.01 broad.
Habitat.—Central Pacific, Stations 270 to 274, surface.
2. Aularia tubularia, n. sp.
Tangential tubes of the network cylindrical, straight, of equal breadth, thorny, covered with numerous short bristle-shaped thorns, which are all of the same length and perpendicular to the tube.
Dimensions.—Diameter of the sphere 3.0; tubes 0.15 long, 0.005 broad.
Habitat.—South Pacific, Station 291, depth 2250 fathoms.
3. Aularia trigonaria, n. sp.
Tangential tubes of the network smooth, very thin in the middle part, gradually dilated towards both ends, so that the nodal points of the network are inflated. (Similar to Aulosphæra sceptrophora, Pl. 109, fig. 3, but without radial tubes.)
Dimensions.—Diameter of the sphere 2.2; tubes 0.1 long, 0.002 broad in the middle part, 0.01 on both sides.
Habitat.—North Pacific, Station 253, depth 3125 fathoms.
Definition.—Aulosphærida with triangular meshes in the network, the tangential tubes of which form a simple lattice-sphere. Radial tubes arise at its nodal points.
The genus Aulosphæra, the first observed form of all Aulosphærida, is also the most common form of the whole family, the richest in distinct species, and widely distributed over all oceans, in the tropical as well as in the temperate and Arctic zones.
The twenty-one species here enumerated may be only a small part of the numerous forms, which may be distinguished according to the different forms of the tubes. One of the two Mediterranean species, which I first described in my Monograph, is cosmopolitan. The shell is in all species a simple regular lattice-sphere with triangular meshes; it differs from the preceding Aularia in the development of radial tubes at the nodal points of the lattice-work.
Definition.—Radial tubes simple, smooth, without terminal teeth and without lateral branches.
1. Aulosphæra trigonopa, Haeckel.
Aulosphæra trigonopa, Haeckel, 1862, Monogr. d. Radiol., p. 359, Taf. x. fig. 4.
Radial tubes of the spherical shell cylindro-conical, straight, smooth, of the same length as the tangential tubes of the network, which are also smooth, straight, cylindrical.
Dimensions.—Diameter of the sphere 1.0 to 2.0; tangential tubes 0.1 to 0.2 long, 0.002 to 0.004 broad.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.
2. Aulosphæra flexuosa, n. sp.
Radial tubes slenderly conical, smooth, gradually tapering towards the distal end, more or less irregularly curved, two to three times as long as the tangential tubes, which are cylindrical, straight and smooth.
Dimensions.—Diameter of the sphere 2.2; tangential tubes 0.15 long, 0.006 broad.
Habitat.—North Atlantic, Færöe Channel (Gulf Stream), John Murray, surface.
Definition.—Radial tubes smooth, without lateral branches or spines, but armed with a verticil of teeth at the distal end.
3. Aulosphæra diodon, n. sp.
Radial tubes cylindro-conical, straight, smooth, of the same length as the smooth, cylindrical, tangential tubes; armed at the distal end with two divergent terminal teeth, which are slightly curved, pincer-shaped, and about one-fourth as long as the tube.
Dimensions.—Diameter of the sphere 2.5; tangential tubes 0.16 long, 0.003 broad.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
4. Aulosphæra triodon, n. sp. (Pl. 109, fig. 8).
Radial tubes cylindrical, straight, smooth, two to three times as long as the smooth, cylindrical, tangential tubes; armed at the distal end with three divergent terminal teeth, which are straight or slightly curved and about one-third as long as the tube.
Dimensions.—Diameter of the sphere 1.2; tangential tubes 0.1 long, 0.01 broad.
Habitat.—North-Eastern Pacific (off Japan), Station 231, surface.
5. Aulosphæra tetrodon, n. sp.
Radial tubes slender, cylindrical, straight, smooth, about three times as long as the smooth, cylindrical, tangential tubes; armed at the distal end with a regular cross of four terminal teeth, which are directed almost horizontally, and are slightly recurved (just as in Aulosphæra spathillata, Pl. 109, fig. 7, but longer and without lateral verticils).
Dimensions.—Diameter of the sphere 1.6; tangential tubes 0.15 long, 0.005 broad.
Habitat.—South Pacific, Station 289, depth 2550 fathoms.
6. Aulosphæra polyodon, n. sp.
Radial tubes slender, spindle-shaped, gradually tapering towards the two ends, smooth, about twice as long as the cylindrical, smooth, tangential tubes; armed at the distal end with a verticil of twelve to twenty or more divergent, conical, slightly curved teeth.
Dimensions.—Diameter of the sphere 3.3; tangential tubes 0.2 long, 0.01 broad.
Habitat.—Central Pacific, Station 272, depth 2600 fathoms.
Definition.—Radial tubes verticillate, armed with a variable number of regular verticils of lateral branches.
7. Aulosphæra verticillata, n. sp.
Radial tubes slender, cylindro-conical, straight, tapering towards the distal end, about as long as the smooth, cylindrical, tangential tubes; armed with eight to twelve verticils of three curved, simple, lateral branches. (Very similar to the tubes of Aulastrum trichoceros, Pl. 111, fig. 5a.)
Dimensions.—Diameter of the sphere 1.6; tangential tubes 0.15 long, 0.008 broad.
Habitat.—South Pacific, Station 300, surface.
8. Aulosphæra spathillata, n. sp. (Pl. 109, figs. 7, 7a).
Radial tubes slender, cylindro-conical, straight, tapering towards the distal end, two to three times as long as the smooth, cylindrical, tangential tubes; armed with two or three distal alternate verticils, each of which forms a horizontal cross of four (sometimes three or five) equidistant branches; their distal ends are on the terminal cross simple hooks, on the proximal cross spathillæ.
Dimensions.—Diameter of the sphere 3.2; tangential tubes 0.12 to 0.16 long, 0.01 broad.
Habitat.—South-Eastern Pacific (off Valparaiso), Station 298, depth 2225 fathoms.
9. Aulosphæra cruciata, Haeckel (Pl. 109, fig. 10).
Aulosphæra elegantissima, R. Hertwig (non Haeckel), 1879, Organism. d. Radiol., p. 90, Taf. ix. fig. 1; Taf. x. figs. 2, 4, 5, 8, 14, 15.
? Aulosphæra pourtalesii, Duncan, 1881, Journ. Roy. Micr. Soc., p. 175, pl. iii. figs. 1-3.
Radial tubes slender, cylindro-conical, straight, tapering towards the distal end, twice as long as the smooth, cylindrical, tangential tubes; armed with four to eight cruciate equidistant verticils, each of which forms a regular cross of four equal, horizontal, lateral branches, bearing at the end a small knob or spathilla.
Dimensions.—Diameter of the sphere 1.2 to 1.8; tangential tubes 0.1 to 0.15 long, 0.003 broad.
Habitat.—Mediterranean (Messina), North Atlantic (Canary Islands), Caribbean Sea.
10. Aulosphæra elegantissima, Haeckel.
Aulosphæra elegantissima, Haeckel, 1862, Monogr. d. Radiol., p. 359, Taf. x. fig. 5; Taf. xi. figs. 5, 6.
Radial tubes cylindrical, straight, twice as long as the smooth, cylindrical, tangential tubes; armed with four to eight equidistant verticils, each of which is composed of eight to twelve simple, horizontal, lateral branches.
Dimensions.—Diameter of the sphere 1.5 to 2; tangential tubes 0.12 to 0.16 long, 0.004 broad.
Habitat.—Mediterranean (Messina), surface.
11. Aulosphæra bisternaria, n. sp. (Pl. 109, figs. 11, 12).
Radial tubes cylindrical, straight, about as long as the cylindrical tangential tubes, smooth or somewhat thorny, armed at the distal end with two alternate verticils of three branches, which bear a terminal spathilla; the proximal branches are twice as long as the distal, and alternate with them regularly, so that the six branches lie in six different meridional planes.
Dimensions.—Diameter of the sphere 2.5; tangential tubes 0.2 long, 0.01 broad.
Habitat.—Antarctic Ocean, Station 156, surface.
12. Aulosphæra dendrophora, n. sp. (Pl. 109, figs. 1, 2).
Radial tubes cylindrical, straight, about as long as the cylindrical, smooth, tangential tubes, armed in the distal half with three verticils of four crossed branches; the four proximal branches are three times as long as the four distal, and twice as long as the four intermediate branches. All twelve branches bear a terminal spinulate knob, and lie in two perpendicularly crossed meridian planes.
Dimensions.—Diameter of the sphere 2.2 to 2.8; tangential tubes 0.2 long, 0.01 broad.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
13. Aulosphæra sceptrophora, n. sp. (Pl. 109, figs. 3, 4).
Radial tubes straight, in the proximal half conical, with inflated base; in the distal half cylindrical, with five or six cruciate verticils, each of which has four perpendicularly crossed teeth. Tangential tubes half as long as the radial tubes, in the middle part very thin, thickened towards both ends.
Dimensions.—Diameter of the sphere 1.2; tangential tubes 0.1 long, 0.002 broad in the middle part, 0.012 on both ends.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
14. Aulosphæra spathophora, n. sp.
Radial tubes slender, cylindrical, more or less curved, about three times as long as the tangential tubes, in the distal half with eight to twelve verticils of six to eight lateral branches, which are forked, decrease in length towards the distal end, and bear on each ramule a terminal spathilla. Tangential tubes slightly curved and thorny. (Similar to Auloplegma perplexum, Pl. 111, fig. 8a, but with a simple lattice-sphere.)
Dimensions.—Diameter of the sphere 2.2; tangential tubes 0.2 long. 0.006 broad.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
Definition.—Radial tubes spiny or thorny, with irregular lateral branches, often with forked distal ends.
15. Aulosphæra bifurca, n. sp.
Radial tubes cylindrical, straight, thorny, twice as long as the smooth, cylindrical, tangential tubes, forked at the distal end, with two curved, convergent, thorny, terminal branches. (Similar to Aulastrum dendroceros, Pl. 111, figs. 4a-4c, but with longer and more spinulate branches.)
Dimensions.—Diameter of the sphere 3.2; tangential tubes 0.25 long, 0.01 broad.
Habitat.—North Pacific, Station 239, surface.
16. Aulosphæra trifurca, n. sp. (Pl. 109, fig. 9).
Radial tubes cylindrical, straight, thorny, about as long as the smooth, cylindrical, tangential tubes, forked at the distal end, with three curved, convergent, terminal branches.
Dimensions.—Diameter of the sphere 2.5 to 3.0; tangential tubes 0.2 long, 0.01 broad.
Habitat.—North Pacific, Station 240, surface.
17. Aulosphæra quadrifurca, n. sp.
Radial tubes cylindro-conical, straight, about as long as the smooth, cylindrical, tangential tubes; studded with numerous irregular lateral branches in the distal half, and armed at the distal end with a cross of four divergent, forked, terminal branches.
Dimensions.—Diameter of the sphere 4.2; tangential tubes 0.2 long, 0.01 broad.
Habitat.—Indian Ocean, Madagascar (Rabbe), surface.
18. Aulosphæra multifurca, n. sp.
Radial tubes cylindrical, more or less curved, three to four times as long as the smooth, often curved, tangential tubes; studded with numerous forked, irregular, lateral branches, and armed at the distal end with a verticil of twelve to sixteen divergent, forked, terminal branches.
Dimensions.—Diameter of the sphere 1.2; tangential tubes 0.06 long, 0.003 broad.
Habitat.—Arctic Ocean, Greenland (Olrik), surface.
19. Aulosphæra coronata, n. sp.
Radial tubes spindle-shaped, tapering from the thicker middle part towards both ends, twice as long as the thorny tangential tubes, studded with numerous irregular, curved, lateral spines, and bearing at the distal end a corona of twenty to twenty-five divergent, curved, terminal branches. (Similar to Auloscena flammabunda, Pl. 110, fig. 4.)
Dimensions.—Diameter of the sphere 3.0; tangential tubes 0.2 long, 0.08 broad.
Habitat.—Tropical Atlantic, Station 347, surface.
20. Aulosphæra undulata, n. sp. (Pl. 109, fig. 6).
Radial tubes slender, cylindro-conical, undulate, about twice as long as the spinulate and undulate tangential tubes; studded with numerous short, perpendicular, lateral branches which are partly simple, partly forked, and bear small terminal spathillæ. The distal end of each radial tube bears usually a verticil of four to eight similar pediculate spathillæ.
Dimensions.—Diameter of the sphere 2.4; tangential tubes 0.2 long, 0.005 broad.
Habitat.—North Pacific, Station 252, surface.
21. Aulosphæra spinosa, n. sp. (Pl. 109, fig. 5).
Radial tubes and tangential tubes equal in size and similar in form, more or less curved, slender, cylindrical, densely studded with numerous irregular spines.
Dimensions.—Diameter of the sphere 1.6; tangential tubes 0.1 long, 0.004 broad.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
Definition.—Aulosphærida with triangular meshes in the network, the tangential tubes of which arise in pyramidal groups of six over the surface of the spherical shell. Radial tubes arise at the tops of the six-sided pyramids, which cover the whole surface.
The genus Auloscena differs from the preceding Aulosphæra, its ancestral form, in a very remarkable and elegant character. The tangential tubes of the network here lie not on a spherical face (as in the latter), but arise over the surface of the spherical calymma in the form of numerous, regular, hexagonal pyramids; each pyramid being composed of six convergent ascending tubes, which are united in a common nodal point; at the latter arises a radial tube, which usually bears an elegant corona of radially divergent terminal branches. Therefore the base of each hexagonal pyramid is in contact at its six corners with the basal corners of six similar neighbouring pyramids, whilst the neighbouring sides of the bases are separated by six regular triangular meshes, which lie on the spherical face. In some species this remarkable and elegant structure is quite regular, whilst in others it becomes more or less irregular.
Definition.—Radial tubes smooth, without lateral branches or spines, bearing a terminal verticil at the distal end.
1. Auloscena mirabilis, n. sp. (Pl. 110, figs. 1, 2).
Radial tubes cylindrical, straight, smooth, about as long as the smooth pyramidal tubes (or the convergent tubes which form the edges of the six-sided pyramids of the network). The distal end of each radial tube bears an elegant spathillate terminal corona (fig. 2), or a verticil of fifteen to twenty curved radial branches, the distal end of which is armed with a spinulate knob.
Dimensions.—Diameter of the sphere 2.0 to 3.0; pyramidal tubes 0.16 to 0.24 long, 0.008 broad.
Habitat.—Central Pacific, Stations 271 to 274, depth 2350 to 2750 fathoms.
2. Auloscena spectabilis, n. sp. (Pl. 110, figs. 8, 9).
Radial tubes cylindro-conical, straight, smooth, twice as long as the smooth pyramidal tubes, armed at the distal end with a conical terminal corona, or a verticil of twelve to sixteen divergent, straight, pointed, terminal branches.
Dimensions.—Diameter of the sphere 4.0 to 5.0; pyramidal tubes 0.25 to 0.3 long, 0.012 broad.
Habitat.—Antarctic Ocean, Station 154, surface.
3. Auloscena pyramidalis, n. sp.
Radial tubes slender, conical, straight, smooth, of the same length as the smooth pyramidal tubes, armed at the distal end with a hexagonal terminal corona, or a verticil of six divergent, straight, pointed, terminal branches, which correspond to the six sides of a pyramid; the proximal apex of this terminal pyramid is opposed to the distal apex of the similar basal pyramid.
Dimensions.—Diameter of the sphere 3.0 to 4.0; pyramidal tubes 0.2 to 0.3 long, 0.01 broad.
Habitat.—Tropical Atlantic, Stations 347 to 349, surface.
Definition.—Radial tubes thorny, with lateral branches or spines, usually with a terminal verticil at the distal end.
4. Auloscena tentorium, n. sp. (Pl. 110, fig. 6).
Radial tubes spindle-shaped, tapering towards both ends, nearly smooth, of the same length as the smooth pyramidal tubes. The distal part of the radial tubes is thorny, and bears a verticil or a corona of twenty to thirty slender terminal branches, which are about one-third as long as the tube, sabre-shaped, with concave outer edge and pointed distal end.
Dimensions.—Diameter of the sphere 4.0; radial tubes 0.3 to 0.4 long, 0.02 to 0.03 broad.
Habitat.—North-Western Pacific (off Japan), Station 231, surface.
5. Auloscena verticillus, n. sp. (Pl. 110, figs. 10, 11).
Radial tubes slender, cylindrical, twice as long as the smooth or somewhat thorny pyramidal tubes, armed in the distal part with two or three irregular verticils of three to six perpendicular spines, and on the distal end with a corona of twelve to eighteen straight, divergent, pointed, terminal branches, which often arise in pairs.
Dimensions.—Diameter of the sphere 3.2; pyramidal tubes 0.15 long, 0.01 broad.
Habitat.—South Atlantic, Station 318, depth 2040 fathoms.
6. Auloscena penicillus, n. sp. (Pl. 110, fig. 3).
Radial tubes slender, cylindrical, thorny, one and a half times as long as the thin and smooth pyramidal tubes, armed in the distal half with densely crowded perpendicular spines and a terminal corona of numerous (twenty to thirty or more) bristle-shaped branches, like a brush.
Dimensions.—Diameter of the sphere 2.0 to 2.5; radial tubes 0.15 to 0.2 long, 0.005 to 0.01 broad.
Habitat.—Antarctic Ocean, Stations 156, 157, surface.
7. Auloscena flammabunda, n. sp. (Pl. 110, fig. 4).
Radial tubes cylindro-conical, twice as long as the thorny pyramidal tubes, studded with numerous curved spines, and armed with a verticil or corona of numerous (twenty to thirty or more) undulate, divergent, pointed, terminal branches.
Dimensions.—Diameter of the sphere 3.0; radial tubes 0.3 to 0.4 long, 0.02 to 0.03 broad.
Habitat.—North Pacific, Station 252, surface.
8. Auloscena gigantea, n. sp. (Pl. 110, fig. 7).
Radial tubes cylindrical, thorny, about as long as the thorny pyramidal tubes, armed in the distal half with four to eight verticils of short curved ciliæ, and at the distal end with a similar small terminal verticil.
Dimensions.—Diameter of the sphere 5.2; pyramidal tubes 0.2 to 0.3 long, 0.01 broad.
Habitat.—Central Pacific, Stations 265 to 268, surface.
9. Auloscena arboretum, n. sp.
Radial tubes cylindrical, straight or slightly curved, about the same length as the smooth pyramidal tubes; armed in the distal half with three or four verticils, tapering in size towards the distal end; each verticil is composed of four crossed and curved branches, which bear a terminal spinulate knob. (This species is very similar to Aulosphæra dendrophora, Pl. 109, fig. 1, and may be derived from it by elevation of the hexagonal pyramids, which in the latter lie in the spherical plane).
Dimensions.—Diameter of the sphere 4.4; pyramidal tubes 0.25 long, 0.01 broad.
Habitat.—Indian Ocean, Cocos Islands (Rabbe), surface.
10. Auloscena serrata, n. sp. (Pl. 110, fig. 5).
Radial tubes spindle-shaped, tapering towards both ends, thorny, twice as long as the thorny pyramidal tubes; armed at the distal end with an elegant corona which is composed of twelve to sixteen curved terminal branches. Each branch bears two opposite series of small recurved teeth and a terminal spathilla of six to eight larger recurved teeth.
Dimensions.—Diameter of the sphere 3.0; pyramidal tubes 0.3 long, 0.012 broad.
Habitat.—South Pacific, Station 298, depth 2225 fathoms.
Definition.—Aulosphærida with triangular meshes in the network, the tubes of which are connected in different directions, and form the spongy wall of a spherical shell. Radial tubes arise on the surface at the nodal points.
The genus Auloplegma, one of the rarest forms of Aulosphærida, differs from the preceding genera in the spongy structure of the lattice-sphere, the thickened wall of which is composed of a loose framework. Numerous tubes, irregularly disposed in different directions, are connected at the nodal points of this loose spongy framework, whilst radial tubes arise on the surface of the latter. Auloplegma exhibits therefore a relation to Aulosphæra, its probable ancestral form, similar to that which Plegmosphæra does to Acanthosphæra among the Sphæroidea.
1. Auloplegma perplexum, n. sp. (Pl. 111, figs. 8, 8a).
Radial tubes straight, cylindro-conical, armed with six to eight verticils of lateral branches, which increase in size towards the base; each verticil is a cross of four dichotomous delicate ramules, ending with a spinulate knob. The length of the radial tube is about equal to the radial diameter of the spongy framework, which forms the thick wall of the spherical shell, and is composed of smooth and straight cylindrical tubes.
Dimensions.—Diameter of the shell 1.5 to 2.0, of its wall 0.3 to 0.4; length of the radial tubes 0.2 to 0.3, basal breadth 0.015.
Habitat.—North Pacific, Station 237, surface.
2. Auloplegma spongiosum, n. sp. (Pl. 111, fig. 9).
Radial tubes slender, straight, cylindro-conical, studded irregularly with lateral branches, which are short, simple, slightly curved, partly verticillate in the distal third, and ending with a small spinulate knob. The length of the radial tubes is about twice as great as the radial diameter of the spongy framework, which forms the wall of the spherical shell, and is composed of thorny or verticillate cylindrical tubes.
Dimensions.—Diameter of the shell 3.2, of its wall 0.1; length of the radial tubes 0.24, breadth 0.01.
Habitat.—North Pacific, Station 231, surface.
Definition.—Aulosphærida with triangular meshes in the network, the tangential tubes of which form a simple, lenticular, biconvex lattice-shell, with shortened vertical main axis. Radial tubes arise at its nodal points.
The genus Aulophacus differs from the common Aulosphæra, its ancestral form, only in the lenticular compression of the spherical lattice-shell, the vertical axis of which is considerably shortened. It exhibits therefore to the latter the same relation as Cenodiscus does to Cenosphæra among the Sphæroidea. The contrary condition is shown in the following genus Aulatractus, in which the vertical axis is prolonged. In the two species of Aulophacus observed the radial spines exhibit a remarkable peculiarity, being longer on the circular periphery of the lens, shorter on both its faces, and shortest in the vertical main axis.
1. Aulophacus lenticularis, n. sp. (Pl. 111, fig. 5a).
Shell biconvex, lenticular, with rounded circular margin; its horizontal diameter three times as great as its thickness (or its vertical main axis). Radial tubes cylindro-conical, straight, with six to nine triradiate verticils, those of the margin of the lens twice as long as the smooth tangential tubes, the others shorter.
Dimensions.—Horizontal diameter of the lens 5.5 mm., vertical main axis 0.2; length of the radial tubes 0.2, breadth 0.01.
Habitat.—Indian Ocean, Belligemma, Ceylon (Haeckel), surface.
2. Aulophacus amphidiscus, n. sp. (Pl. 111, fig. 5b).
Shell discoidal, slightly biconvex, with rounded circular margin; its horizontal diameter five times as great as its thickness. Radial tubes cylindrical, covered with numerous short thorns, those of the margin of the lens three times as long as the smooth tangential tubes, the others shorter.
Dimensions.—Horizontal diameter of the lens 6.0, vertical main axis 1.2; length of the radial tubes 0.2, breadth 0.005.
Habitat.—Indian Ocean, Madagascar (Rabbe), surface.
Definition.—Aulosphærida with triangular meshes in the network, the tangential tubes of which form an ellipsoidal or spindle-shaped, simple lattice-shell, with prolonged vertical main axis. Radial tubes arise at its nodal points.
The genus Aulatractus differs from all the other Aulosphærida in the peculiar prolongation of the vertical axis of the lattice-sphere, by which the latter becomes ellipsoidal or spindle-shaped. The triangular meshes of the regular lattice-work become usually more or less irregular and polygonal at the two poles of the elongated main axis. Aulatractus seems to be developed from Aulosphæra in the opposite way from Aulophacus, the former by elongating, the latter by shortening of the vertical main-axis.
1. Aulatractus fusiformis, n. sp. (Pl. 111, figs. 6, 6a, 6b).
Shell spindle-shaped, about twice as long as broad, rounded at both poles of the main axis. Tangential tubes smooth, cylindrical. Radial tubes of the same length as the tangential tubes, but much thinner, slender cylindrical, studded with perpendicularly arising, short, lateral branches, which are scattered in the proximal part, verticillate in the distal part, and bear a spinulate terminal knob.
Dimensions.—Length of the shell 7.5 to 10.0, breadth 3.5; length of the radial tubes 0.15 to 0.18, breadth 0.004.
Habitat.—Tropical Atlantic, Stations 348, 349; surface, and in various depths.
2. Aulatractus diploconus, n. sp. (Pl. 111, fig. 7).
Shell diploconical or nearly spindle-shaped, about three times as long as broad, equally pointed at the two poles of the main axis, not inflated in the middle part. Radial tubes slenderly conical, thorny, only half as long as the smooth tangential tubes.
Dimensions.—Length of the shell 6.0 to 8.0, breadth 2.2 to 4.5; length of the radial tubes 0.1 to 0.15, breadth 0.007.
Habitat.—North Atlantic, Canary Islands, Station 353, surface.
3. Aulatractus fusulus, n. sp.
Shell spindle-shaped, about twice as long as broad, pointed at the two equal poles of the main axis. Radial tubes cylindro-conical, smooth, about as long as the smooth tangential tubes. This species resembles in its simple structure the common cosmopolitan Aulosphæra trigonopa, and differs from it only in the constant spindle-form of the shell.
Dimensions.—Length of the shell 6 to 8, breadth 3 to 4; length of the radial tubes 0.16 to 0.2, breadth 0.008.
Habitat.—North Atlantic, Færöe Channel, Gulf Stream (John Murray); Hebrides (Mœbius).
4. Aulatractus ellipsoides, n. sp.
Shell ellipsoidal, about twice as long as broad, with equally rounded poles on the main axis. Radial tubes straight, cylindrical, verticillate, about twice as long as the smooth tangential bars; each verticil is cruciate, composed of four rectangularly crossed, short, lateral branches which bear a small spathilla at the distal end.
Dimensions.—Length of the shell 6.6, breadth 3.6; length of the radial tubes 0.2, breadth 0.01.
Habitat.—South Atlantic, Station 332, surface.
Definition.—Network of the shell with polygonal, usually irregular meshes; three or four tangential tubes usually being united at each nodal point.
Definition.—Aulosphærida with polygonal meshes in the network, the tangential tubes of which form a simple smooth lattice-sphere. No radial tubes at the nodal points.
The genus Aulonia is the simplest form of the subfamily Aulonida, or of those Aulosphærida in which the lattice-work of the shell is composed not of triangular but of polygonal meshes; all these Aulonida are much rarer and much less differentiated than the Aularida or the common Aulosphærida with triangular meshes. Aulonia has the same simple, smooth, spherical lattice-shell as Aularia, and differs from it only in the polygonal form of the meshes, which, however, is very constant.
1. Aulonia tetragonia, n. sp.
Meshes regular or subregular, square, sometimes intermingled with a variable number of irregular, triangular, and pentagonal meshes. Bars cylindrical, of equal breadth.
Dimensions.—Diameter of the spherical shell 2.0 to 3.2, of the meshes 0.12 to 0.18; breadth of the bars 0.008.
Habitat.—Antarctic Ocean, Station 154, depth 1800 fathoms.
2. Aulonia pentagonia, n. sp.
Meshes subregular, pentagonal, intermingled with a smaller number of quadrangular and triangular irregular meshes. Bars cylindrical, of equal breadth.
Dimensions.—Diameter of the spherical shell 2.8 to 3.2, of the meshes 0.15 to 0.2; breadth of the bars 0.01.
Habitat.—South Pacific, Stations 293 to 302, depth 1375 to 2270 fathoms.
3. Aulonia hexagonia, n. sp. (Pl. 111, fig. 1).
Meshes regular or subregular, hexagonal, often intermingled with a variable number of pentagonal and heptagonal meshes. Bars cylindrical, of equal breadth.
Dimensions.—Diameter of the spherical shell 2.5 to 3.3, of the meshes 0.15 to 0.25; breadth of the bars 0.012.
Habitat.—Tropical Atlantic, Stations 347 to 349, surface.
4. Aulonia metagonia, n. sp.
Meshes subregularly alternating, larger octagonal and smaller tetragonal. The network of this remarkable species has a striking similarity to the arrangement of the radial tubes in some species of Sycon, figured in my Monograph of the Calcispongiæ (1872, Bd. iii., Taf. ix. fig. 12).
Dimensions.—Diameter of the sphere 4.4, of the greater octagonal meshes 0.24 to 0.3, smaller tetragonal 0.1 to 0.12; breadth of the bars 0.007.
Habitat.—Indian Ocean, Cocos Islands (Rabbe), surface.
5. Aulonia polygonia, n. sp.
Meshes irregular, polygonal, variable in form and unequal in size; the majority usually pentagonal or hexagonal, but numerous intermingled meshes with three, four, seven, or eight sides. Very variable in the size of the bars and the form of the meshes.
Dimensions.—Diameter of the sphere 2.5 to 5.5, of the meshes 0.1 to 0.2; breadth of the bars 0.008 to 0.12.
Habitat.—Cosmopolitan; Atlantic, Indian, Pacific, surface.
Definition.—Aulosphærida with polygonal meshes in the network, the tangential tubes of which form a simple lattice-sphere. Radial tubes arise at its nodal points.