﻿CEPHALASPID^. 



177 



Postero-lateral cornua exceeding the shield in 



length Eitkeraspis (p. 193). 



II. Anterior dorsal body-scales fused into a con- 

 tinuous plate. 

 Cornua divergent ; shield larger than the 



dorsal plate Auchenaspis (p. 195). 



Cornua rudimentary and bordering the dorsal 



plate, which is larger than the shield. . . . Didymaspis (p. 199). 



Genus CEPHALASPIS, Agassiz. 



[Poiss. Foss. vol. ii. pt. i. 1835, p. 135.] 



Syn. Eucephalaspis, E. R. Lankester, Fishes Old Red Sandst. pt. i. 

 (Pal. Soc. 1870), p. 43. 

 Hemicyclaspis, E. R. Lankester, ibid. p. 43. 

 Zenaspis, E. R. Lankester, ibid. p. 43. 



Postero-lateral angles of shield more or less produced into acute 

 cornua, not exceeding the shield in length. Body elevated, and 

 triangular in transverse section. Flank-scales in three series, the 



Fig. 18. 



Cepkalaspis lyelli 

 antorbital 

 groove; i. p. 

 cells ; p. o. v 

 cornu ; p. r., 



upper series of 

 series deepest, 

 often serrated ; 



PART II. 



Ag. — Outline sketch of shield, restored by Lankester. a. /., 

 see; a. p., antorbital prominences; i.g., interorbital ridge or 

 , interorbital prominence ; o. r., orbital rim ; m. c, marginal 

 ,, postorbital valley ; p. a., posterior angle ; p. c, posterior 

 posterior ridge ; p. s., posterior spine ; r., rim. 



each side meeting in the mesial line above, the middle 

 and the lowermost forming an infero-lateral fringe 

 ventral scales apparently small, arranged in V-shaped 



