NATURAL SCIENCES OF PHILADELPHIA. 201 



of the maxillary, appears to coincide to some extent with other peculiarities 

 of the species. It appears under the following modifications : 



a. Deep, enclosed, so as to be a blind canal ; 

 D. doris, clymene. 



/?. Shallower, open, but strongly marked ; 

 D. s ty x, Delphinapterus peronii, D. delphis, (less marked.) 



y. Very shallow, little marked ; 

 D. asthenops et var., microps, crotaphiscus. 



Delphinus doris Gray, Catal. Brit. Mus. Zool. Erebus, Terror tab. 



One specimen, habitat unknown, from the Museum at Salem, Mass., agrees 

 closely with Gray's indications, with, however, a shorter occiput than repre- 

 sented in his figure. The triangle is marked with numerous curved grooves 

 which converge, and are convex, backwards. The cranium is quite as heavy 

 as that of the t u r s i o. The sella turcica is more strongly marked than in 

 the other species, and the processus olivaris much more prominent and solid. 

 The basioccipital is not grooved for the medulla oblongata ; the paroccipital 

 alae are well developed. The glenoid cavity sends a groove upwards on the 

 inner border of the squamosal process, but its inner border is not pro- 

 longed into an extended lamina towards the sphenoid bounding the periotic 

 elements in front, as in the Delphinapterus. The palatines have not the 

 strong external ridge seen in the latter and the D. crotaphiscus. Teeth 



3 5 * , i- 



in. lines 



Length from end of muzzle to convexity of occ. condyle. 16 4 



" " notch 9 9 



" from notch to middle of occipital crest 5 4 



" ofgonys 1 11 



Width at notch 4 



" at postorbital processes 7 10 



" between temporal crests 6 5 



Delphinus clymene, Gray, Cat. Cetac, p. 115. Zool. Ereb. & Terror, 39. 



That this species is an inhabitant of the coasts of the United States, is proven 

 by the specimen in the Museum of the Academy from off New Jersey, pre- 

 sented by John Krider, of this city. Its peculiarly flat occiput distinguishes 

 the cranium at once from that of its congeners ; in other respects it is not un- 

 like the s t y x of our collection. 



Length of muzzle to notch 11*25 in. 



From end of muzzle to foramen magnum 18 



Length of gonys 1*5 



" from notch of muzzle to foramen magnum 6 - 25 



" " foramen magnum to occipital crest 4 



Breadth between temporal ridges 6*5 



" " angles of mandible 3 - 87 



" at notch of muzzle 4*25 



Delphinus styx, Gray, 1. c. 117. Zool. E. T., pi. 21. 



One cranium, Morton collection. Habitat unknown. 



Length from end of muzzle to notch 10 in. 



" " notch (straight) to foramen magnum 7 " 



" " " to occipital crest 5 " 



" ofgonys 1*75 in. 



Breadth at notch of muzzle 4*25 " 



" between temporal ridges (straight) 6*75 " 



" " angles of mandible 3*50 " 



Delphinus asthenops, sp. nov. 



Two crania of this species before me are light and rather slender, though 



1865.] 



