BRITISH FOSSILS. 



Decade IX. Plate Y. 



CENTROLEPIS. Gen. Nov. 



[Genus CENTROLEPIS ^Kivrpov, calcar ; Xeiris, squama). Egkrton. (Sub-kingdom 

 Vertebrata. Class Pisces. . Order Goniolepidoti. Family Sauroidei. Sub-family Sau- 

 roidei homocerci.) Head large ; teeth conical ; body short ; pectoral and anal fins very 

 broad ; scales rhomboidal, rugose, with strong spurs on the posterior margin.] 



Species Unica. Centrolepis asper. Poiss. Foss. vol. 2. p. 304. 



Walking, many years ago, with Lord Enniskillen, on the beach 

 under Black Yen, to the eastward of Lyme Regis, we met a well- 

 known character, by name Jonas, who had just split open a lias 

 nodule which contained a fossil fish. The specimen changed owner- 

 ship for a few shillings, and from that day I have in vain searched 

 for another fragment to elucidate the affinities of this most singular 

 fish. The family to which it appertained was for some years 

 doubtful. Professor Agassiz, who examined it more than once, was 

 inclined to refer it to the Lepidoidei. More recently, by delicate 

 manipulation, the form of the jaws and characters of the teeth have 

 been discovered, and they unquestionably betoken its affinity to 

 the Sauroidei. 



Description. — The distorted position of the fish, and the deficiency 

 of the dorsal portion, render the restoration of the actual proportions 

 a matter of conjecture. The head is large, and the mouth especially 

 so ; the body short, and the pectoral and anal fins unusually broad. 

 It is fair to presume, from these features, that the depth of the fish 

 was considerable, and the dorsal fin large. By restoring the head 

 to its natural position, the length of the fish from the nose to the 

 base of the tail is ascertained to be seven inches. Of this dimen- 

 sion the head occupies nearly three inches. The cranial bones are 

 dense, and are ornamented externally with a raised pattern, varying 

 from a granular to a ridge and furrow figure. On the opercular 

 flap the pattern is less prominent, and is associated with what 

 appear to be lines of successive growth, corresponding with the 

 existing outlines of the constituent plates. The mouth measures 

 two inches in length. The teeth are numerous, sharp, and conical ; 

 the intervals between the larger ones being beset with smaller ones. 

 No fish of the Lepidoid family has the dental apparatus similarly 

 [ix. v.] 9 F 



