364 Messrs. Hancock & Atthey on Reptile- and Fish-Remains 



never could have written as he has recently done respecting 

 PaUeoniscuSj Amblypterus^ Pygopterus^ PolypteruSj and Lepi- 



Acanthodopsis Wardi, sp., Egerton. 



For some time past one of the authors of this paper has had 

 in his collection several jaws of a fish with large triangular 

 teeth, five or six in number, and appearing like processes of 

 the bone ; and of so peculiar a character are they that it was 

 impossible to say even to what family of fishes they belonged. 

 It was not until similar specimens were found associated with 

 other remains, that any light could be obtained respecting 

 them. At length a crushed head or two were procured exhi- 

 biting the same peculiar jaws with the like curious teeth 

 attached, lying in juxtaposition with the spines of one of the 

 Acanthodei, partially buried in what appeared to be the broken- 

 up skin of the fish, crowded with minute rhomboidal scales. 

 In one specimen the two pectoral spines are placed in their 

 proper position behind the head, and united to it by the con- 

 tinuity of tissue, so as to leave no doubt that they and the 

 head belonged to the same fish. The uniting tissue, too, was 

 mainly composed of granule-like scales of a lozenge-form. A 

 tail likewise of an Acanthodian has occurred in the same 

 locality, the scales on which agree both in size and character 

 with those found with the heads. It is therefore quite certain 

 that the jaws alluded to belong to the Acanthodei, notwith- 

 standing the abnormal character of the teeth, which in this 

 family are usually described as minute and conical. 



In the genus Acanthodes, indeed, the teeth appear to have 

 been determined only in one species, though M. Agassiz states, 

 in his description of the genus, that fine teeth disposed in 

 a simple range appear to garnish the circumference of the 

 mouth *. The species in which the teeth have been deter- 

 mined is A. 2ntsillus ; and of this the same author writes that 

 the mouth is " garnie de tr^s-petites dents qui, meme sous une 

 tr^s-forte loupe, ne paraissent que comme des petits points 

 noirs " f- This is so definite that it is impossible to doubt its 

 accuracy ; we are therefore forced to the conclusion that in 

 this genus, as at present understood, there are two very dis- 

 tinct kinds of dentition, so distinct, indeed, that it seems ne- 

 cessary to establish a new genus for the reception of those 

 species which, like A. Wardi, may have large triangular 

 teeth, similar to those alluded to. We therefore propose the 

 generic appellation of Acanthodopsis for those Acanthodei 

 with this peculiar dentition. 



* Poissons Fossiles du Vieux Gres Rouge, premiere livraison, p. 39. 

 t Ibid. p. 36, ■ 



