Dr. J. E. Gray on the Amphishanians. 375 



The head-shields in both these specimens are exactly alike, the 

 central crown-shield being much broader than long ; the hinder pair 

 of frontal shields rather shorter than the front pair, and narrower on 

 the central edge by the angular front edge of the crown-shield ; the 

 two pairs of occipital shields are shorter than broad, the hinder pair 

 being the smaller, and in one instance coalesced on one side with the 

 plate of the front pair. 



They all have a brown spot on the centre of each of the dorsal 

 scutella. 



** Sternal plates all separate, symmetrical. Sphenocephalus. 



2. Lepidosternon Grayii, A. Smith, MS. Brit. Mus, 



Head rather short, broad ; the vertebral plate hexagonal, elon- 

 gate, as long as broad; the frontal plate very short and broad; 

 the parietal shields oblique ; the occipital much longer than broad ; 

 temporal shields larger on the side of the occipital ; plates of the 

 sternal disk symmetrical, in oblique diverging lines. 



Hab. South America? (Brit. Mus.). 



Sternal disk formed of four diverging lines of uniform, similar- 

 sized, symmetrical shields ; the shields on the central line smaller, 

 being divided down the centre by a straight suture. 



In 1848, Dr. (now Sir Andrew) Smith sent to the British Museum 

 this specimen, with the name of Lepidosternon Grayii, informing me 

 that he had described (or intended to describe) it in the ' Proceedings 

 of the Zoological Society ' under that name. I cannot find that it 

 has been so described, nor can I find any notice of it in any other 

 work, though it is very like, but evidently distinct from, the Lepido- 

 sternon pJioccena of Dumeril and Bibron, figured by M. d'Orbigny 

 (Voy. Amer. Merid.). 



Fig. 6. Fig. 5. 



Lepidosternon Grayii. 



3. Leptdosternon phoc^na, Dum. et Bibr. Erp, Gen. v. 507 ; 

 Gray, Cat. Tortoises, &c., B. M. 73 ; D'Orbigny, Voy. Amer. Me'rid. 

 Kept. t. 6. f. 7-10. 



Head broad ; the vertebral plate elongate, small, larger than broad, 

 acute at each end ; the frontal and occipital plates large, shorter than 

 broad, the frontal the largest ; the parietal plates short, broad, band- 

 like ; the plates of the sternal disk uniform, symmetrical, oblique. 



Hab. Buenos Ayres {Bridges, B. M. : stuffed). 



