21 



fisli, which was dried without any ])ii|)aration whatever. 

 From the extreme thinness of ihc body, this phm has an- 

 swered pretty well, and there does not ajipear to have been 

 any material alteration of the natural form. The specimen 

 was presented to the British Museum, by His lilxcellency 

 Captain George Grey, Governor of South Australia. On 

 account of the flexibility of its spinous rays, it ought pro- 

 bably to be ranged with the Gohiidai, among which there 

 is already another apodal genus, viz. AinirrliiclKiK, but it 

 does not possess a genital papilla, and the internal anatomy 

 is unknown. In external form, and in the general appear- 

 ance and sculpturing of the bones of the head, Pal<ccus 

 has some analogy to Agriopux, just as C/ueiiichi/ii/s re- 

 sembles Triyla. The habits of the fish are unknown to us. 

 This fish is very much compressed, thinning olT on the 

 dorsal line to the mere thickness of the bases of the dorsal 

 rays, but being obtuse on the belly, before the anus. The 

 up]ier profile is parabolic, the curve rising from the over- 

 hanging forehead to its summit at the twelfth ray, which is 

 opposite to the base of the pectorals. The descent to the 

 caudal fin is longer, and more gradual. The face, in de- 

 scending towards the mouth, inclines considerably back- 

 wards, in a slightly concave line. The rictus of the 

 mouth is nearly horizontal ; the under jaw is equal in 

 length to the upper one, and lies nearly in a straight line 

 with the thorax and belly, as far as the anus. There is a 

 little ascent from the anus to the horizontal under profile 

 of the tail. The height of the posterior part of the tail is 

 scarcely one-eighth of that of the body at the pectorals. 

 The greatest thickness of the fish appears to be at the con- 

 vex gill-covers, and the compression to augment posteriorly, 

 but as the specimen has been dried, the exact thickness at 

 the shoulder cannot be ascertained. 1 he anus is midway 

 between the upper lip and the base of the caudal. 



The head, measured iiom the brow to the gill-opening, 

 forms nearly a third of the total length, caudal excluded. 

 It is extremely narrow, on a front view jircscnting nothing 

 but the thin edges of the frontal bones, connected by a 

 narrow stri])e of membrane, which, in the dried specimen, 

 forms a furrow, the eyes and nostrils being entirely lateral. 

 The eyes are high up on the cheeks, and the nostrils, which 

 are minute, are nearer the profile. The upper opening is 

 between two descending processes of the anterior frontal, 

 and the lower one, which has a tubular margin, is about 

 half way between the eye and the upper lip. 



The mouth, small and low down, is formed above 

 entirely by the intermaxillaries, which are moderately 

 protractile, their pedicles being about half as long as the 

 limbs. The maxillaries widen gradually towards their 

 lower rounded ends, and are longitudinally scul])tured. 

 The lower jaw equals the upper one in length, and its 

 limbs are porous beneath, several of the pores having pro- 

 jecting lips forming minute barbels. The intermaxillaries 

 and lower jaw are armed with very minute teeth, like 

 gi'ains of sand, densely crowded into a moderately wide 

 band. The vomer and palate-bones are smooth. The 

 pharyngeal bones and the sessile hemispherical rakers are 

 armed with nearly microscopical villifonn teeth. 



The suborbitar chain appears to be a mere row of mem- 

 branous tubes, curving across the cheek iiom the temples 

 at a considerable distance beneath the eye. The preor- 



bitar is, howe\cr, well developed, and presents, close to 

 the mouth, an oval bony disk, sculptured in a stelliform 

 manner. A narrow process rises from before the cheek, 

 to meet a point of tht; anterior frontal, near the angle of 

 the eye ; there is a minute point or tooth on the same side 

 of the disk, in connexion with the suborbitar chain ; two 

 others, equally small, exist on the other side, next the 

 maxillary, and the two ends of the disk are obtuse. The 

 bone is level with the integument, and does not cover any 

 part of the maxillary. 



The frontal bone is arched over the eye, and is entirely 

 lateral, its thin edge only being seen above or anteriorly. 

 It is sculptured, as are also the occipital and suprascapular 

 bones. The preoperculum is curved cUiptically, its upper 

 limb being wiaest, and somewhat triangular ; the narrower 

 under limb descends considerably, as it runs forward to 

 the angle of the mouth. At the union of the lindjs, ]ios- 

 teriorly, there is a small corner, rendered more distinct by 

 the course of the lines on its surface. The edge of the 

 bone is otherwise entire. The interoperculiim ascends ob- 

 liquely as it runs backwards, and widens posteriorly in a spa- 

 tulate manner. The operculum comes in forwards for nearly 

 half its length above the upper disk of the preoperculum, 

 and the lines on its surface run towards two distinct points 

 on its posterior margin. The suboperculum is rather over 

 than behind the interoperculnm, and has a nearly rectan- 

 gular disk. All these bones are sculptured, as is also the 

 humeral chain, but none have either pungent teeth, or 

 serratures. 



The gill-membrane edges the gill-cover, and ends at 

 the upper angle, in a small peak, with a notch anterior 

 to it. It is supported by six rays, the upper one 

 curving round the opercular bones to the upper angle. 

 The 0])ening runs under the throat up to the chin, the mem- 

 brane having no attachment to the isthmus, and no con- 

 nexion with its lellow, except at the point of attachment 

 to the lower jaw. 



The dorsal fin commences at the anterior top of the 

 forehead, before the eye, and reaches to the end of the 

 tail, being united to the caudal fin. Its spinous rays are 

 rather stout at the base, particularly anteriorly, but flexible 

 at the tips. The second, third, and fourth are tallest; the 

 following ones become gradually shorter to the fifteenth or 

 sixteenth, alter which they increase in length on to the 

 eighth articulated ray. This gradation of the rays, con- 

 joined with the curve of the back, gives an almost straight, 

 or slightly concave line to the edge of the fin, with a 

 rounding ofi' towards the end of the tail. 



The jointed rays taper, and are notreadily distinguishable 

 by the'naked eye from the posterior spinous ones. There 

 are two or three pairs of minute membranous processes on 

 the side of the second dorsal ray, and one pair on the third 

 ray. The caudal fin is slightly rounded at the end, eight 

 of its rays being nearly of the same length, while the two 

 lower ones are shorter and graduated. 'l"he anal fin, with 

 considerably less height than the posterior part of the 

 dorsal, apitroaches to it in form. It is not connected with 

 the caudal, but the last ray is bound to the tail by mem- 

 brane. The pectorals are large, over-reaching the anterior 

 third of the anal, and are attached near to the ventral sur- 

 face. Their rays are slender and tapering, with the tips 



