16 



FOSSIL FISHES OF THE ENGLISH CHALK. 



the four anal fin-spmes distinctly borne hy separate supports. Some of the large, 

 thin, serrated scales are Avell displayed, while the thickenings and bendings pro- 

 duced by the sensory canal of the lateral line are also conspicuous. The general 

 proportions of the fish, noted in the specific diagnosis and indicated in the accom- 

 panying restoration (Text-fig. 4), are better shown by the original of PI. Ill, 

 fig. 1, and by many similarly preserved specimens. As proved by B. M. no. 

 49043, the lower l)order of the abdominal region is gently rounded or flattened, not 

 keeled. 



The cranium (PL III, fig. 2 ; Text-fig. 5 u) closely resembles that of Beri/x 

 (Text-fig. 5 a), especially in the arrangement of the ridges and hollows on the 





Fig. 5. Eoof of cianium ut Btnji, il i, adadijl us, Cnv. and Val. (h). Hop! outcry:!' Icir.-sii'iisis (Mautell) 

 (B), and Hoplopteryx sim-us, A S Woodw. (C). eth., mfMtlnii..i.l ; /,-.. tVcntal; sncc, siipra- 

 occipital crest in fossa originally occupied by muscles ; o, mcliau slinic-cavity ; i, ii, m, lateral 

 paired slime-cavities ; arrows indicating passages through tlio a\ alls of the slime-cavities. 



roof ; but the ethmoidal region is relatively larger than in thi^ 

 The parasphenoid is slender, and there is a large basicranial canal (B. M. nos. 

 P. 5687-88). The occipital plane is inclined backwards and downwards; and 

 the low median supraoccipital crest (socc.) is produced backwards over it. As in 

 Beryx, the supraoccipital witli its crest is sunk in a deep trough formed by a pair of 

 laminar ridges (PI. Ill, fig. 2, v.), which are deepest behind on the otic region and 

 gradually converge forwards until they meet in a short median ridge at the anterior 

 end of the frontal region. Again as in Beri/,r, this large median trough is crossed 

 by a less elevated transverse ridge in its anterior narroAV portion ; and the small 

 triangular cavity thus formed (o) opens into the lateral frontal cavities l)y two 



