300 GIBBES' NEW SPECIES OF MYLIOBATES, ETC. 



PL AT AX, Agassiz. 



A singular bone has been sent to me from the Pliocene marl of Darlington, South 

 Carolina, which Professor Agassiz considers the interapophyseal bone that supports 

 the dorsal spines of Platax — a genus of Ctenoid fishes still existing in our present 

 seas. Several views of a specimen are here given, PI. 42, figs. 11, 12, 13. 



SQUALIDiE. 



CAKCHARIAS. 



In my monograph of the Fossil SqualidcE of the United States, I mentioned 

 having met with a fragment of what I considered a Carcharias. I have recently 

 found among some specimens from the Eocene of Ashley river, one of which is 

 figured in PL 42, fig. 8. Professor Agassiz agrees with me that it is a true 

 Carcharias. It resembles that described by him as C. tenuis. Until others are 

 found I am unable to decide upon its specific characters. 



CARCHARODON. 



C. LEPTODON, Agassiz. I have recently identified this species from the Eocene of 

 Orangeburg, South Carolina, PL 42, figs. 7, 9. It has the form of the variety of 

 C. angustidens, figured by Professor Agassiz as C. heterodon, though it is more 

 slender and acutely pointed. The absence of the lateral denticles and the slenderness 

 are its specific characters. The serratures appear also to be more minute. 



GALEOCERDO. ~ 



The figure PL 42, fig, 10, represents a symphyseal tooth of a species of Galeocerdo. 

 I have not seen the specimen, but am indebted to Capt. A. H. Bowman of the 

 Topographical Engineers, U. S. A., for a drawing of it, found in the Eoce?ie sand 

 of Ashley river near Charleston, South Carolina. 



REFERENCE TO PLATE XLII. 



Figs. 1,2. Myliobates Holmesii, Gibbes. 



Fig. 3. Edge view of the same. 



Fig. 4. Myliobates transversalis, Gibbes. 



Figs, 5, 6, 5a. Ptychodus polygyrus, Agassiz. 



Figs. 7, 9. Carcharodon leptodon, Agassiz. 



Fig. 8. Carcharias. 



Fig. 10. Symphyseal tooth of Galeocerdo. 



Figs. 11, 12, 13. Interapophyseal bone of Platax, Agassiz. 



