180 DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 



uneven but flattish disc of the tooths The dental surface of each jaw is triangular, the 

 apex of the triangle curving outwards between the labial cartilages over the lip so as 

 to be visible when the mouth is closed. The exterior lips are not greatly developed, 

 but the lining of the mouth is transversely wrinkled, the fold next the dental surface 

 being the largest. The branchial apertures are smooth lunated slits. The vent is 

 situated at the widest part of the ventral disc, and anterior to the middle of the total 

 length of the fish, snout, and caudal fin included. 



Dorsal fins ovato-falcate, the first one commencing at the end of the ventrals, and 

 rather exceeding the second one in size. Caudal unequally oval, the lower lobe having 

 a more curved outhne than the upper one, and the apex of the ellipsis being above the 

 level of the point of the tail. The height of the fin is rather less than half its length. 



The skin is smooth, without the fine reticulations into which the skin of Torpedo narke 

 corrugates in spirits ; and its colour is an uniform yellowish-brown, without spots. 

 The under surface is pale. 



Anatomical observations. — The skull is wider than that of Narcine brasiliensis, particu- 

 larly between the auditory protuberances and the nasal apophyses, the sides of the 

 skull there being straight, not incurved. The perforation marked c in Henle's figure, 

 t. 7. f. I. 3., does not exist in the side of the snout cartilage of Narcine tasmaniensis, 

 and the anterior cornua of this cartilage are deeply notched, whereas they are entire in 

 brasiliensis. The two small triangular cartilages (F. G.) which occupy the space be- 

 tween the snout cartilages and the naso-pectoral processes {schddel-brust-jiossen-knorpel) 

 in brasiliensis are also wanting in tasmaniensis, their place being supplied by a fibrous 

 membrane. The jaws oi Narcine tasmaniensis are much stouter, and have less span than 

 those of Torpedo narke, being stronger in particular at the articulation, where broad 

 processes project from behind the snout in both jaws, whereas these processes are but 

 slightly indicated in T. narke. The lip cartilages of tasmaniensis are elliptical and 

 acute, and the upper ones are entire, being without the small notch at the mesial end, 

 which exists in brasiliensis. The palatine cartilages are more cylindrical than those of 

 brasiliensis. The pectoral girdle is less wide, and is strengthened by broader connect- 

 ing plates than in Torpedo narke, but the semilunar range of cartilages which supports 

 the pectoral rays is less stout. 



The vertebrae are 119 in number ; the first, as in narke, very long, with large, broad, 

 triangular, transverse processes. The transverse processes of the two next vertebree 

 are scarcely evident, but afterwards, up to the fourteenth inclusive, they are uniformly 

 rather short, narrow, and flat. The fifteenth and five following vertebrae send out long 

 slender processes like ribs, four or five times the length of the preceding transverse pro- 

 cesses. The twenty-first, twenty-second, and twenty-third have a more lateral ridge, 



' The surface of a tooth reflects the light in such a way under the microscope, that there is much difficulty 

 in ascertaining its true form. The teeth resemble those of Astrape capensis. 



