262 AMERICAN JOURNAL 



of the shells, the narrower aperture, the downward slope of the 

 lahrum, the columella without a twist and the prominent plait at 

 base are all characters of the Nassinae and not of Buccinum. 

 Dr. Gill in his diagnosis states that the labrum is " smooth 

 within," and yet quotes Buccinuvi porcinum, Say, as a species, 

 though it has prominent lines within. The fact is there are two 

 groups, in one of which the labrum is smooth within and not 

 thickened on the submargin as in P.fossulata, Con., P. multiru- 

 gata, Con., and the other has a slightly thickened labrum near 

 the margin and is striate within, as Buccinum 2^orcinumy Say. 

 These again are linked v^\i\\llyanassa^ Stimpson,* the typical spe- 

 cies of which has a striated labrum and is not thickened, and has 

 the plait at base very like B. ijorcinum, which plait is thicker 

 than that of the typical species, and the shell is more elongated. 

 This is related to Tritia trivittata, Say, which is still more elon- 

 gated, so that it is difficult to separate all these genera or subge- 

 nera by invariable characters. I have a new Miocene shell closely 

 related to T. trivittata, which has a striate labrum like that shell, 

 whilst another, equally near to that species, T. peralta, Con., 

 has the labrum entire. These genera or subgenera are all alike 

 in having a plait at the base of the columella. 



Dr. Stimpson, in his generic character of Ilyanassa has "inner 

 lip smooth," but specimens which I found at Jersey City have 

 it very distinctly striate. It will be proper to accept Ptycho- 

 salpinx as a genus or subgenus ; if the latter, Buccinum porci- 

 num, Say, will constitute the type of a subgenus. The differences 

 may be thus stated. 



Ptychosalpinx. — Labrum not thickened, entire ; species 

 P. altilis, Conrad, P. laqueata, Con., P.fossulata, Con., P. hilix^ 

 Con., P. lienosa, Con., P. midtirugata, Con., P. scalaspira, Con., 

 P. Tuomeyi, [Buccinum,) H. C. Lea. Buccinum lamjms, 

 Brocchi is probably a species of this genus as well as B. Escherij 

 Mayer. 



^MhgQWViS PARANASSA, Conrad. 



Description. — Shell with the submargin of labrum slightly 

 thickened within and striate-; siphonal canal shorter than in the 

 above group. Species Bucc. porcinum, Say, B. aratum, Say, 

 Tritia harpuloides, Con., Paranassa yranifera, Con., Tritia 

 sexdentata, Con., and Buccinum elongatum, Sowerby, an Eo- 

 cene shell. This group is well represented in the environs of 

 Dax, as may be seen in Grateloup's Conch. Fossil, pi. 1, fig. 4, 

 5, 27. The group of which Nassa trivittata, Say, is an example, 



* Jour. Conch, i., p. 61, 1866. 



