1895.] J-'J < [Cope. 



the right side. In the other hand the right premaxillary is pierced near 

 the aaterior part of the vomerine crest by a large round foramen, which 

 is wanting from the left side. A large foramen pierces the inner side of 

 the lateral crest half-way to the superior border, and opposite the middle 

 of the left blow-hole. 



The dental alveoli are subrouad, and are separated by narrow septa. 

 They are not deep, the deepest equaling 50 mm., so that the teeth have 

 been easily lost. 



Measurements. 



M. 



Length of fragment on middle line 800 



Width of skull at supraorbital notch ; left side restored 800 



Width of muzzle where broken off 173 



Widtli of right premaxillary at middle of length 100 



Width of left premaxillary at middle of length 150 



Width of right premaxillary at vomerine keel 100 



Width of left premaxillary at vomerine keel 170 



Elevation of lateral crest above orbit (apex broken off) 310 



Length of series of eight teeth 165 



From Drum Point, Chesapeake Bay, Maryland. 



CIIONEZIPHIID^. 



ZipJiivice Flower ; Ziphiidce Gill {ZipMus preoccupied). 

 Pelycouhamphcs pertortus, gen. et sp. nov. 



Char. gen. — Allied to Choneziphius, but the solid rostrum of the vo- 

 mer bifurcates posteriorly and embraces a basin which takes the place of 

 the maxillary basin of the right side, and reduces that of the left side to 

 very small dimensions. Blow-holes very unsymnietrical, the left only 

 preserved in the specimen. 



This genus has certain characters which ally it to the Physeteridse. 

 The internareal part of the vomer is directed very obliquely upwards to 

 the left, and then forwards to the left on the superior surface for a dis- 

 tance, when it turns to the right as in Paracetus and Cogia. Instead of 

 terminating at this point as in those genera, it assumes the swollen form 

 and dense structure seen in the species of Clioneziphius, and besides send- 

 ing forwards the usual rostrum on the median line, it continues to the 

 right, and apparently spreads out into a thin plate which forms the floor 

 of a wide basin, and which apparently continues to and forms its right 

 border, overlying the posterior plate of the maxillary. This basin is repre- 

 sented in Paracetus mediatlanticus by a longitudinal shallow concavity of 

 the right side of the superior keel of the vomer, which is a rudiment as 

 compared with the basin in the present genus. The rostrum of the vomer 

 extends to the narrow extremity of the specimen, where it is broken off. 

 The fracture exhibits no tube or channel. 



PROC. AMER. PUILOS. SOC. XXXIV. 147. R. PRINTED MAY 29, 1895. 



