168 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



chalk of North America, approximate very closely to this species. 

 Should they be identical, it will prove this to be one of the most 

 widely distributed fossil forms of fishes with which we are ac- 

 quainted. 



Corax incisus Eg. — A second species of Corax occurs in the 

 Indian collection sent over by Mr. Cunliffe, of small size 

 and very distinct character. It is rather smaller than 

 the species of this genus generally are, corresponding in 

 this respect with Corax planus, of which some imper- 

 fect specimens are figured in the "Poissons Fossiles" from an 

 unknown locality. Our specimens are not perfect, but they are 

 sufficiently so to prove them to be specifically distinct from all 

 those figured and described by Agassiz. The principal cusp is 

 conical, rather slender, and pointed. It is more upright and less 

 falcate than usual. The antero -posterior diameter of the tooth is 

 small, in this respect resembling Corax planus. The character of 

 the marginal armature is peculiar. It is rather notched or crenu- 

 lated than serrate, the subdivisions of the edge being blunt and 

 irregular. The lateral. cusp is smooth, and corresponds with its 

 principal in the character of its dentelures. 



Otodus ? marginatus Eg. — Several of the Indian squaloids 

 are apparently referable to the genus 

 Otodus. Of these, two have some re- 

 semblance to the common Otodus ap- 

 pendiculatus of the chalk formation ; 

 and although the characters of this 

 species, as at present recognised, are 

 wide enough to embrace an extensive 

 variety of forms, yet they are suffi- 

 ciently defined to exclude the Indian 

 specimens. The larger species, of 

 which I have found four specimens, is 



remarkable for the rapid increase of the antero -posterior diameter 

 of the shaft as it approaches the base. The latter is thick and 

 massive, with a deep depression on the outer surface. The cone 

 in profile is regularly and distinctly incurved from the apex to the 

 junction with the base. It is narrower than in most specimens of 

 O. appendiculatus. The outer surface is smooth and rounded ; 

 the inner one is also smooth, and more arched than in any species I 

 am acquainted with. A section, taken one third distant from the 

 base, would represent the inner face of the tooth as nearly semi- 

 circular. The cutting edge is sharp, and so distinct as to have the 

 appearance of a border, separated from the remainder of the shaft 

 by a shallow groove. The lateral cusp is large, conical, and sharp, 

 having more resemblance in these respects to this feature in the 

 odontaspid teeth. The corresponding cusp is broken ; but the 

 fracture shows that, in all probability, the tooth was symmetrical. 



Otodus basalts Eg. — A tooth sent to England by Mr. Cunliffe 

 has a closer resemblance to 0. appendiculatus than the species last 



