MEMOIR UPON A NEW ICHTHYOPTERYGIAN FROM THE KIMMERIDGE 

 CLAY OF GILLINGHAM, DORSET, 



By J. C. MANSBL-PLBYDBLL, Esq., 

 P.G.S., P.L.S. 



UVIER says, in the " Ossemens Fossiles," the 

 Ichthyosaurus was first made known to the 

 scientific world through the pages of the 

 Philosophical Transactions in 1814, from a 

 specimen found in the lias of Lyme Regis, 

 comprising a well-preserved head and several 

 other bones. Cuvier's memoir shows the relation of the shoulder 

 with that of the crocodile ; of the nares, sclerotic bones of the eye, 

 and the vertebrse with those of the fish, as well as the absence of a 

 sternum. These latter peculiarities led Kcenig, who was then 

 Keeper of the Mineralogical Department of the British Museum, 

 to give to the family the generic name Ichthyosaurus. It presents a 

 combination of forms which are found separately in various orders 

 of vertebrates; it has the teeth of the crocodile, the head of a 

 lizard, the vertebrse of a fish, the paddle of a whale, and the 

 palate is essentially similar to that of the existing Rhynchoce- 

 phalian genus Sphenodon, of which the living Hatteria is the sole 

 representative. The head partakes of the character of the 

 crocodile in the form and arrangement of the teeth, and with the 

 lizard in the position of the nares, which are set in the region of 



