708 



APPENDIX. 



[No. VI- 



a radiated sub-orbicular plate on each side of the snout. The nostrils are double, very 

 small, and placed close to the orbit. The anterior foramen, formed in the soft border 

 of the posterior one, has a raised margin. The snout is immoveable, and truncated. 



Mouth. — The intermaxillary bones, forming about one-third of the margin of the 

 upper jaw, lie transversely, overlapping the curved articulating extremities of the 

 maxillaries, and give a truncated form to the snout. The maxillaries are very thick 

 and strong, are made up of two plates, have a lanceolate shape with smooth edges, 

 and, when the mouth is shut, pass on the outside of, and cover the broad flattened 

 sides of, the lower jaw. They send a small curved process behind the extremities of 

 the intermaxillaries to be articulated through the medium of cartilage with the snout. 

 The under jaw is strong, has an obtuse and very slightly tuberculated extremity, 

 which projects four or five lines beyond the upper jaw. Its articulation, extending as 

 far back as the posterior part of the orbit, admits of considerable depression, but 

 the opening of the mouth is not of corresponding magnitude, as its sides are con- 

 tracted by a tendinous or muscular fold, which runs from the middles of the superior 

 maxillaries to the sides of the lower jaw. 



Teeth. — The intermaxillary bones, the extremity of the lower jaw, the palate, 

 vomer, and tongue, are covered with card-like plates of minute teeth. The same 

 kind of plates occur at the root of the tongue, and on the superior and inferior pharyn- 

 geal bones. 



The branchiostegous membranes contain ten flat curved rays, which increase con- 

 siderably in breadth, and slightly in curvature and length, as they approach the 

 operculum. 



The branchial arches are furnished with solitary rows of rigid cartilaginous awl- 

 shaped processes, whose inner surfaces are rough, with minute teeth. Those on the 

 upper arch exceed half an inch in length ; the others are smaller. 



The oesophagus and stomach descend from the pharynx in form of a continuous tube, 

 having nine longitudinal rugae on its internal membrane. After running towards the 

 anus for about three inches, this tube makes a short turn upwards, and terminates 

 in the pylorus. 



The cceca are very numerous, conical, or awl-shaped, and about a quarter of an 

 inch long. They surround the intestine, and are much crowded from its com- 

 mencement to the insertion of the gall-duct, a space of about two inches. Be- 

 yond this they are continued down one side of the intestine only for two inches 

 more. The remainder of the gut descends naked in a straight line to the anus. 

 About an inch and a half of the gut, a short way from the anus, is furnished with 

 circular rugse. The air-bladder is large, without contractions, and communicates 

 freely with the upper part of the stomach, or lower part of the oesophagus. There 

 is a large spleen attached to the curvature of the stomach. 



