NORTH! A. 



fascicle ; aperture rhombo-ovate, oblong ; lajjrum entire, not sinuous, 

 smooth within ; columella inversely sigmoidal, concave near the middle, 

 with a very thin callous deposit and with a revolving linear plait in front. 



Tertiary, United States and Fru/. 



Dr. Gill refers his genus to the family Buccinidae, but I agree with the 

 late Mr. Conrad that his description indicates ('as do the types cited) 



P. ALTILIS, Conrad. PI. 3, fig. 28. Miocene, Virginia. 



P. SCALASPIRA, Conrad. PI. 3, fig. 29. Miocene, Virginia. 



Subgenus PARANASSA, Conrad. Differs from PtycJwsalpinx in the 

 submargin of the labrum being slightly thickened within and striate ; 

 si phonal canal shorter. Eocene, Miocene, America and Europe. 



P. GRANIFERA, Conr.* PI. 3, fig. 30. Virginia. 



Subgenus TRITIARIA, Conrad. Elongated, subturrited, labrum not 

 thickened within. This does not seem to differ generically from the true 

 Nassas ; it has very little resemblance to Ptychosalpinx. 

 T. PERALTA, Conrad. PI. 3, fig. 31 . Miocene, Virginia. 



[BuLLioPSis, Conrad. Placed by its author at first as a subgenus of 

 Nassa, it was subsequently removed by him to Melanopsidae. It has some 

 resemblance to Bullia. ] 



Ucmis NORTHIA, Gray. 



The animal of this genus is unknown, but the operculum has 

 been figured by H. and A. Adams, in their " Genera." The 

 shell is in its general aspect much closer to Pnxionella in the 

 family Terebridse than to the getiera with which it is here (and 

 has been heretofore) associated ; the variceal thickening at or 

 near the outer lip, is however, a feature which does not obtain in 

 the Terebridse. Pusionella, moreover, has a concentric oper- 

 culum, with its nucleus near the middle of the inner margin. 

 Perhaps the figured operculum of Northia is abnormal; 

 it has that appearance. I think that if these shells had not 

 been assigned to the Nassidse or to any other family, I would 

 have placed them in Terebrida? : as it is, I prefer to allow them 

 to remain here, rather than possibly complicate the subject In- 

 changing their position. 



* As one of the two specimens of the type of Paranassa is striate 

 within the aperture, while the other is smooth, probably the distinction 

 from Ptycfiosalpinx will not hold good. 



