712 



APPENDIX. 



[No. VI. 



rior margins are rotundate and entire, or very slightly undulated ; those on the an- 

 terior part of the belly are much smaller than the others. 



Head. — The vertex is covered with smooth skin, which, shrinking, shews in the 

 dried specimen a central obtuse ridge, and a lateral one over each orbit, better 

 marked, but tuberculated and interrupted. These are inconspicuous in the recent 

 fish. The operculum and sub-operculum form conjointly nearly a rectangle, having 

 its posterior angles slightly rounded off. The inter-operculum is acutely triangular, 

 and the prae-operculum, of a lunated form, unites with the sub-orbitar bones to cover 

 great part of the cheek, a small fleshy portion occurring only over the angle of the 

 lower jaw. The orbit is large and nearly round ; it is above one-half nearer to the 

 margin of the mouth than to the posterior edge of the operculum. 



The nostrils are small, and placed between the anterior superior angle of the orbit, 

 and the intermaxillaries. 



The mouth is moderately large. The intermaxillaries, forming about a third part 

 of the upper mandible, are narrow, and lie transversely, giving a truncated appear- 

 ance to the snout when viewed from above. They are articulated with the maxil- 

 laries, which have also a narrow oblong form ; and, when the mouth is extended, 

 they form its sides, descending perpendicularly to be connected by membrane with 

 the broad posterior part of the lower jaw ; an oblong pedicle is attached to the pos- 

 terior edge of each of the maxillaries. The lower jaw is large and strong, and has its 

 articulation under the centre of the orbit ; about one-half of it, when the mouth is 

 open, projects beyond the upper jaw. Its symphysis, or extremity, is obtuse, form- 

 ing the segment of a circle. When the mouth is closed, the maxillaries are retracted 

 close to the orbit, the lateral margins of the lower jaw shut in under them, and a 

 transverse slit only is seen, formed at the extremity of the muzzle, by the intermaxil- 

 laries, and obtuse end of the lower jaw. 



Teeth. — A single row of small hooked teeth runs round the margins of the inter- 

 maxillaries, maxillaries, and lower jaws. A double row, rather more minute, exists 

 on each side of the palate, and there is a small cluster on the anterior part of the 

 vomer. These are all conspicuous in the dried specimen. The tongue is smooth ; 

 the superior pharyngeal bones are rough, with minute teeth. 



The upper branchial arch is furnished with a row of rough subulate cartilaginous 

 processes; there are smaller and softer processes on the other arches. The branchios- 

 tegous membrane contains eight flat rays, the inner ones becoming gradually more 

 curved. 



The alimentary canal descends from the pharynx for two inches and a half, in form 

 of a straight tube, having its internal membrane disposed in coarse longitudinal 

 rugae; it then dilates considerably, and bends upwards upon itself. This dilated 

 part resembles the stomach of the attihhawmegh in its structure, but its coats are 



