Discoveries in Australia Volume I Part 43

RADII. BR. 6; D. 3 : 23; A. 3 : 12; C. 21; P. 18: V. 1, 5.

FISHES. PLATE 2. Figures 1, 2, 3, 4, and 5.

This fish is as thin in the body as a lath, whence the generic name. Its greatest width is at the cheek, as shown by the section figure 3, where the transverse diameter is about half the height. Figure 4 shows the section at the gill cover, and third dorsal spine, where the thickness is less; and figure 5, represents a section behind the ventrals, where the thickness is little more than a t.i.the of the height, and it gradually decreases to the caudal fin. The oblong profile is highest at the third dorsal spine, whence it descends with a slightly convex curve to the mouth, which is low down--the under jaw when extended, being nearly on a line with the belly. The height of the tail between the vertical fins is equal to half the greatest height of the body. The dorsal and ventral lines are both acute, especially the former, and the medial line of the nape continues acute to the orbits.

The length of the head, measured from the upper jaw, is contained four times and a half in the total length of the fish. The large round eye, situated near the upper profile, fills more than a quarter of this length. The orbit is surrounded by a ring of muciferous ca.n.a.ls, with open orifices, which are the only exterior vestiges of the suborbitar chain.

The small mouth descends obliquely and scarcely reaches back to the orbit. The intermaxillaries are moderately protractile, but the lower jaw, when depressed, projects still further forward. The maxillary widens towards its lower end, which curves a little forwards. Three pores exist on each limb of the lower jaw.

The teeth of the upper jaw present a fine, but rather uneven and broad cardiform surface at the symphysis, which narrows to a single row towards the corner of the mouth, where they are a little longer and more subulate. Four canine teeth stand across the end of the jaw anterior to the dental plate, the intermediate ones being shorter than the outer ones. The dent.i.tion of the under jaw differs in the dental band being narrower, and in there being a conspicuous canine in the middle of each limb of the jaw. There are also six canines standing across the extreme tips of the jaw, opposed to the upper ones. Most of the teeth are slightly curved backwards. The chevron of the vomer projects from the roof of the mouth, and its surface is armed by minute teeth in about three or four densely crowded rows. The palatine teeth are still more minute, and the band is four or five deep. The teeth, when examined with a lens, appear to be very acute and in nowise spherical. The pharyngeal teeth are subulate and acute, and of unequal heights. There seems to be only one inferior pharyngeal bone below; but without dissection this could not be clearly made out. The outer branchial rakers are long.

The narrow, slightly pitted, scaleless disk of the preoperculum bounds the scaly cheek behind and below, and has an entire edge with neither spine nor acute angle at the bend. The other pieces of the gill cover are closely covered with scales, only a little smaller than those of the body. The pretty wide thin inter-operculum lays freely over the gill membranes, and covers them when shut up. The sub-operculum is minutely crenulated on the edge, and has a small sub-membranous tip, which projects a little beyond the three opercular teeth. A small curved notch marks the separation between the interoperculum and sub-operculum.

The scales extend on the crown of the head to the middle of the orbits.

The snout, lips, jaws, the place at the corner of the mouth over which the maxillary glides and the gill membrane are scaleless. The scales of the body are very regularly disposed, showing rhomboidal disks when in situ, with strongly ciliated edges. The lateral line ascends at its commencement and bends rather suddenly under the first soft dorsal ray to run near and parallel to the ridge of the back. It terminates beneath the sixth ray from the end of the fin, but recommences on the fourth scale beneath, and runs in the middle height of the tail to the base of the caudal. Two or three of the scales before its recommencement, have a minute pit in the middle of their disks, as is not unusual with the Glyphisodons. The first part of the lateral line forms an almost continuous tubular ridge traced on thirty-eight scales of the second row from the summit of the back; the posterior part traverses six or seven scales. There are twelve or thirteen scales in a vertical row on the side of the body.

The a.n.u.s, situated a short way before the a.n.a.l fin, has a very small aperture.

There are no scales on the fin membranes. The three dorsal spines are short, graduated, moderately stout, and pungent. The twenty-three soft rays are all distinctly articulated, and more or less branched. The last ray is divided to the base, and is graduated with the two preceding ones, giving a rounded form to the posterior tip of the fin. The specimen had the anterior part of the fin frayed a little, so that it is probable that the soft rays are higher and less distinctly branched than the artist has represented them to be in copying the example placed before him. The ventrals are in a line with the tip of the gill cover and first soft dorsal ray, and from the extreme narrowness of the pelvis are close to each other. They are tapering, pointed, and overlap the beginning of the a.n.a.l, which, though it have fewer rays than the dorsal, is similar in structure. The pectoral and caudal are much rounded, especially the latter. There is a greater s.p.a.ce between the a.n.a.l and caudal than between the dorsal and the same fin. In the caudal there are twenty rays, including two very short ones above, and the same number below.

The general colour of the specimen, which has been long in spirits, is shining yellowish-brown with several round dots of azure-blue scattered over the body. The cheek is crossed obliquely by a row of three spots.

The figure errs in representing the spots as dispersed over the cheek; they are in fact ranged in a row. Length, 2 1/2 inches.

HABITAT. Coast of Australia.

Haslar Hospital, 28th October, 1845.

APPENDIX.

DESCRIPTIONS OF SOME NEW AUSTRALIAN REPTILES.

BY JOHN EDWARD GRAY, ESQUIRE, F.R.S., ETC.

Fam. SAURIDAE.

SILUBOSAURUS, Gray.

Head subquadrangular, raised in front, head-shields flat, thin, rather rugose. Nasal shields ovate, triangular, rather anterior, with a groove behind the nostril. Rostral shields triangular, erect. Supranasal none; internasal broad; frontonasal large, contiguous; frontal and interparietal small, frontoparietal and parietal moderate; eyebrow shields, 4-4. Temples scaly, no shields between the orbit and l.a.b.i.al plates. Eyes rather small, lower lid opatic, covered with scales. Ears oblong, with a large scale in front. Body fusiform, roundish thick; scales of the back, broad, lozenge-shaped, keeled; keels ending in a dagger point; largest on the hinder parts of the throat and belly; transverse, ovate, 6-sided. Limbs four, strong. Toes elongate, compressed, unequal, clawed; tail short, conical, tapering, depressed; with rings of large, broad, lozenge-shaped, dagger-pointed, spinose scales, with a central series of very broad 6-sided smooth scales beneath.

This genus is intermediate between Cyclodus and Egernia, but quite distinct from both. It differs from Tachydosaurus and Cyclodus in having slender elongated toes like Egernia, in the scales being keeled, and in there being no series of large plates beneath the orbit, and it is easily known from Egernia by the tail being depressed and broad, instead of conical and round. Like all the genera above named, it appears to be peculiar to Australia.

The Silubosaure. Silubosaurus stokesii.

REPTILES. PLATE 1.

Olive brown, varied with black and large white spots; shields of the head white, black-edged.

Inhabits Australia.

EGERNIA, Gray.

Head quadrangular, rather tapering in front. Head shields convex, rugose.

Nasal shields ovate-triangular, rather anterior, approximate; supranasal none; rostral triangular, erect; internasal lozenge-shaped, as long as broad; frontonasal rhombic, lateral, separate; frontal and interparietal moderate, elongate; frontoparietals 2, rather diverging, contiguous in front; parietal moderate, half ovate. Temple shielded. Orbit without any scales between it and the l.a.b.i.al shields. Ears oblong, with 4 small scales in front. Body fusiform. Scales of the back, sides, and upper part of the limbs broad, 6-sided, with a large central keel ending in a spine, larger on the loins, those of the nape 3- or 5-grooved, of the throat and belly thin, broad, ovate, 6-sided. Legs 4, strong. Toes elongate, compressed, unequal, clawed. Tail as long as the body, round, tapering, with 6 series of broad 6-sided, keeled, strongly-spined scales, with a series of broad 6-sided smooth scales.

Cunningham's Egernia. Egernia cunninghami.

Tiliqua cunninghami. Gray, Proceedings of the Zoological Society 1832 to 1840.

REPTILES. PLATE 2.

Olive, white spotted head, brown chin, and beneath white; ears with 3 or 4 pointed scales in front.

Inhabits Australia.

Fam. AGAMIDAE.

CHELOSANIA, Gray.

Head large, covered with small rather unequal not imbricate scales. sides of the face rounded, without any large scales upon the edge of the eyebrows. Parotids swollen, unarmed. Nostrils lateral, medial. Throat lax, with a slight cross fold behind. The sides of the neck unarmed. Nape and back with a crest of low angular distant scales. Body compressed, with rings of rather small rhombic keeled rough uniform scales placed in cross rings; of the belly rather larger, obliquely keeled; of the limbs larger. Tail elongated, tapering, rather compressed, with keeled scales, those of the under sides rather truncated, the keel of the scales of the end forming ridges, the upper surface slightly keeled, subdentated. Toes 5-5, moderate, unequal. Femoral and prea.n.a.l pores none.

The Chelosania. Chelosania brunnea.

Pale brown, rather paler beneath.

Inhabits West Australia.

GINDALIA, Gray.

Head moderate, subquadrangular, covered with regular keeled scales, of the occiput rather smaller. Face-ridge rather angular, edged with small scales. Parotids rather swollen, with a ridge of rather larger conical scales over the ears above. Nostrils lateral, medial. Throat rather lax, with a cross fold behind. Nape and back rounded, not crested. Scales of the back equal, rhombic, keeled, placed in longitudinal series; on the sides smaller, but with the keels forming rather ascending ridges; of the belly similar, in longitudinal series, with the keels sharp and rather produced at the tip. The tail round, tapering, with imbricate rhombic seales, with the keels forming longitudinal ridges. Femoral and prea.n.a.l pores none. Toes 5-5, unequal.

GINDALIA, Gray.

The Gindalia. Gindalia bennettii.

Pale brown, rather paler beneath; the scales of the back small, sharply keeled, forming longitudinal ridges, which converge together just at the base of the tail towards the two upper ridges formed by the keels of the scales of the tail; of the limbs rather larger.

Inhabits North-West coast of Australia.

GRAMMATOPHORA.

The Crested Grammatoph.o.r.e. Grammatophora cristata.

Olive; head black varied, beneath pale; throat, chest and under side of the thighs black; tail black-ringed; scales rather irregular, with a central and two lateral series of compressed keeled scales; nape with a crest of compressed elevated distant scales; sides of the neck with scattered single elongated conical spines; tail tapering, with uniform keeled scales, keeled above, rather dilated at the base, with indistinct cross series of rather larger scales.