THE 



GEOLOGICAL MAGAZINE. 



No. XCIV.— APRIL, 1872. 



I.-On theEosteal Prolongations of Squalobaia polyspondyla, Ag. 



By William Davies, 



Of the British Museum. 



(PLATE IV.) 



FEW amongst the many remains of Fossil Fishes hitherto dis- 

 covered have excited more interest than the remarkable fossil 

 Eay, found about forty years ago by Miss Anning in the Lower 

 Lias at Lyme Eegis. 



This specimen, which is preserved in the Bristol Institution, was 

 first described by Dr. Eiley, who says, " The form of this animal is 

 so striking and peculiar, that the majority of observers have dis- 

 agreed not only as to its genus, but even as to its class ; for by the 

 generality it has been pronounced a Saurian." ^ 



However, he rightly determined its zoological position, and 

 pointed to its affinity with the Eays in most of its characters, and 

 to the true Sharks in some others. Hence his generic name of 

 iSqiialor'aia. 



Prof. Agassiz subsequently examined the specimen, and gave a 

 description of it, illustrated by two fine plates, in his great work on 

 Fossil Fishes.'^ He there corrects the error which Dr. Eiley had made 

 in supposing that the prolongations in front of the head were the 

 jaws of the animal, whereas they formed but a snout analogous to 

 that of the genus Fristiophorus. Agassiz adopts Dr. Eiley 's name 

 for the genus, instead of that of Spinacorliinus, which he had pre- 

 viously proposed for it. 



Another fine example of this interesting fossil fish (PI. IV. 

 Fig. 1), also from the Lias of Lyme Eegis, has just been secured for 

 the National Collection through the interest of Sir Philip Egerton, 

 one of the Trustees, and the Earl of Enniskillen, which has served 

 to throw some light upon what was previously obscure as to the 

 true nature of the terminal prolongations of the head. As the object 

 of this paper is solely to direct attention to these " prolongations," 

 it may be advisable to reproduce here all that has been advanced in 



1 Geol. Trans., 2nd ser., vol. v., p. 83. 



2 Each. Poiss. Foss., torn, iii,, p. 384, tab. 42, 43. 



VOL. IX. — NO. XCIV, 10 



