ELASMOBRANCHI1. 35 



Abbott's Monmouth County example is more compressed at 

 the crown than the other examples. It also has flaring trenchant 

 edges, and its inner face basally is swollen. His Mullica Hill 

 examples agree largely with Da Costa's, which, in turn, differ 

 from Maryland Miocene examples 1 in the slightly deflected 

 crown, the latter more convex on its inner surface. 



The present species does not seem to have been recorded pre- 

 viously from New Jersey, except if confused with Isurus min- 

 utus, as contended by Eastman. 



In the Geological Survey collection I have examined 2 teeth 

 without data, and 34 from Shiloh in Cumberland County (E. 

 Davis) [from the so-called Shiloh marl of the Kirkwood (Mio- 

 cene) formation, K.], probably belonging to this species. 



Isurus hastalis (Agassiz). 



Oxyrhina xiphodon Cope, Proc. Amer. Philos. Soc. Phila., XIV, 1875, p. 

 362 (Cumberland Co. Miocene). 



Anterior teeth broad, thin, compressed, widely triangular. 

 Crown slightly curved outward towards apex. Outer coronal 

 surface flat or slightly concave, rarely with basal vertical wrin- 

 kles, and inner surface moderately and evenly convex. Apex 

 usually deflected a little laterally. Cutting-edges entire. Some- 

 times an obselete broad short convex basal cusp at one or each 

 side of base. Root short, with usually blunt obtuse edges, outer 

 surface flattened or slightly concave, inner surface moderately 

 convex, and lower profile a little emarginated. Lateral teeth 

 with coronal edges gradually curving to ends of base, and apex 

 often slightly deflected externally. Length reaches 47 mm. 



This species is known only from its detached teeth, usually to 

 be identified by their broad and thin appearance. Woodward 

 says it is almost impossible to distinguish many of the postero- 

 lateral teeth from those of Isurus desorii and the existing Isurus 

 oxyrinchus. He suggests Otodus apiculatus Agassiz, with a 

 rudimentary lateral denticle as a synonym. The present species 

 does not seem to be very numerous among New Jersey fossils. 



1 Oxyrhina desorii Cope, Proc. Acad. Nat. Sci. Phila., 1867, p. 142. 



