MUSEUM OF COMPARATIVE ZOOLOGY. 177 



The specimens were perfectly fresh, but did not contain the soft parts. The 

 generic place therefore remains a little doubtful. So far as the shell is con- 

 cerned, it does not differ from Liomesus, unless in the somewhat narrowed aper- 

 ture. In some respects the shell recalls Dalium, but wants the prominent band 

 in front of the suture and is of a much more Buccinoid form. It is dedicated 

 to the memory of Dr. Wm. Stimpson, the author of the genus, which was 

 long erroneously included with the Buccinums. 



Subfamily BUCCININjE. 



Genus PISANIA Biyona. 



Subgenus TRITONIDEA Swainson. 



Pisania pusio Lin. (non Auct.) is widely spread through the Antilles, and 

 was collected at Key West from the hermit crabs by Captain Pickering, U. S. N. 

 It has many synonyms, and when young is strongly striated. These young 

 with the epidermis on resemble P. striata Gmelin very much, and have been 

 so labelled in collections, but the true striata (+ maculosa Lam. Tryon) is a 

 Mediterranean form. To the dark striated variety of pusio are to be referred 

 P. wthiops Phil, and P. janeirense Phil. 



The transition between Pisania proper (P. pusio) and Tritonidea is easy. 

 Take P. pusio var. cethiops and compare it with a small specimen of T. varie- 

 gata, or a smooth variety of T. iincta, from which there is no difficulty in reach- 

 ing T. auritula via the ribbed varieties of T. tincta. I can only regard Tritonidea 

 as a subgenus of Pisania. 



Of the group Tritonidea, the region under consideration affords T. cancellaria 

 Conrad (-+- T. floridanus Petit), T. tincta Conrad, T. auritula Link (+ T. coro- 

 mandelianus Lam., + T. ringens Tryon non Reeve, -f- lauta Reeve,), T. vari- 

 egatus Gray (+ T. vivcrratoides Orb.), T. UOrbignyi Payr. (21 fms., off Cape 

 Catoche, Yucatan), and T. limbata Phi]., provided this last, elsewhere referred 

 to in this paper, really belongs to this group. Of this list T. auritula is, so 

 far as we know, Antillean ; T. cancellaria extends from the Caribbean to Texas 

 and Florida; T. tincta extends from Cape Hatteras southward to Mexico and 

 the northern Antilles ; T. variegatus is rare everywhere, but reaches the Florida 

 Keys ; while T. limbata and D" 1 Orbignyi are known to me by specimens from 

 only one or two localities. The T. Haneti of (Petit according to) Tryon is not, 

 in my opinion, a Tritonidea. The T. ringens of Calkins and Tryon, from 

 specimens submitted by those gentlemen, is T. tincta, pure and simple, and has 

 no particular resemblance to T. ringens, which is a West American species. 



Genus PHOS Montfort. 



Notwithstanding the error of Mr. Tryon's statement that this genus is sepa- 

 rated by good conchological characters from Nassa, I do not doubt its validity, 

 but the differences are to be found in the soft parts and the operculum, not in 

 vol. xvm. 12 



