520 E. TTTLLEY NEWTON ON THE REMAINS OF 



the parasphenoid ; while two others may, perhaps, be pieces of 

 pectoral spines. 



Locality and Distribution. — As already stated, the specimen above 

 described was obtained from the Gault of Folkestone ; but the 

 particular bed from which it came cannot be ascertained. Portions 

 of a pair of mandibles, evidently belonging to this species, but only 

 about half the size of the Gault specimen, are preserved in the 

 British Museum (No. 40146) ; and these are from the Lower Chalk 

 of Hailing. Fragments of this species are also to be found among 

 the fish-remains from the Cambridge phosphatic deposits. 



ICHTHYODECTES, Cope. 



This genus, as defined by Prof. Cope (I. c. pp. 189 and 205), in- 

 cludes those forms which, while agreeing with Portheus in their 

 main characters, differ from that genus in having the teeth nearly 

 equal in size throughout. The only English specimens referable to 

 this genus with which I am at present acquainted, are : — the one 

 figured in Dixon's ' Geology of Sussex ' (pi. 32*. fig. 9), and named 

 (without any description) Hypsodon minor ; and the small jaw from 

 the Toulmin-Smith collection described below, i". elegans. The 

 first of these is referred to by Cope (I. c. p. 206), and considered by 

 him to belong to the genus IcJitJiyodectes. An examination of the 

 original, which is now in the British Museum (No. 28894), con- 

 firms this determination. Parts of both rami of the mandible 

 are preserved ; and while the right side (that figured by Dixon) 

 has the teeth most perfect, the left side, most fortunately, has the 

 articular portion preserved ; and this exhibits the peculiar form 

 found in Portheus and Ichthyodectes. The uniform size of the teeth 

 allies it most closely to the latter genus. 



Ichthyodectes minor, Egerton. (PI. XXII. fig. 14.) 



Hypsodon minor, Egerton ; Dixon's ' Fossils of Sussex,' pi. 32*. 

 fig. 9, p. xiv. 



The specimen above alluded to, which was obtained from the 

 Chalk of Sussex f, seems to be more closely allied to /. anaides and 

 /. ctenodon than to either of the other species described by Prof. Cope ; 

 but it differs from these, and, apparently, from all the other species, in 

 the possession of remarkably straight teeth, which are not curved in- 

 wards as is usually the case. The teeth are hollow ; and there is evi- 

 dence of about eighteen in each ramus, not reckoning the spaces be- 

 tween them, which are in most cases occupied by alveoli, and possibly 

 by broken teeth, the total number of alveoli being about thirty to 

 thirty-three. The alveolar margin is nearly straight, with a slight 

 convexity towards its anterior end. Upon the outer surface, towards 



t There is no locality with this specimen at the British Museum ; and none 

 is mentioned in Dixon's ' Sussex ; ' but in Prof. Morris's Catalogue, page 330, 

 it is given as "Chalk, Sussex?; Charing." 



