INSTITUTE OF SCIENCE, PHILADELPHIA. 423 



specimens show dark lineations, which differ from those of the preceding 

 species in being less evidently radiating, more broken, and much more 

 close-set. 



The only other North American species which has an edentulous pillar- 

 lip is A''. Shozvalteri Lea, a shell closely related to N . fluviatilis of Europe and 

 having a different form of aperture. It is a recent species found, so far, only 

 in the fresh water of the Coosa River, Alabama. 



It is somewhat singular that none of the recent species of the region are 

 found in the Caloosahatchie Pliocene, and is perhaps to be accounted for by 

 the sandy shores, which are not favorable to Nerites. Gabb has mentioned 

 N. viridis as found fossil in Santo Domingo, but has not specified the horizon 

 or locality. 



Superfamily ZYGOBRANCHIA. 

 Family PLEUROTOMARIID^. 



The Miocene and Pliocene of the Southern States have not yet offered 

 any examples o{ Pleitrotoniaria, though there is every reason to suppose that 

 they will eventually be found. In the Eocene a large and fine species, recalling 

 P. Adansoniana, has been described by Tuomey (Proc. Acad. Nat. Sci. for 

 1852, p. 193, 1854) from the limestones of Wilmington, N. Carolina, under the 

 name of Trochus nixus. It has never been figured, but a fine specimen is in 

 the National Collection from the original locality. Conrad has also named a 

 large species from the Shark River, New Jersey, Eocene as P.perlata,hut it is 

 hardly definitely established as yet. The family Haliotidce is also, so far, 

 unrepresented by species in the Floridian Pliocene, though Pourtales dredged 

 a species in the Florida Strait which was associated with several other mol- 

 lusks like Bothrocorbida, which are found not uncommonly in the Caloosahat- 

 chie beds. 



Family FISSURELLID^. 

 Subfamily FISSURELLIDEINvE. 



Mr. Pilsbry, in his revision of the Fissiirellidce, has pointed out that the 

 typical subfamily does not antedate the Pliocene ; as far as yet known, all the 

 earlier forms belong to the subfamily EmargimdiiKE . The collections upon 

 which this memoir is based entirely sustain this view. In fact, so far, only 

 two species are reported from our Tertiary which do not belong to the group 

 just mentioned, and they are also found living in the same region. 



Genus LUCAPINELLA Pilsbry. 



Lucapinella limatula Reeve. 



Fissurella limatula Reeve, Conch. Icon., f. 115, 1851. 

 Fissurellidea limalula Dall, Rep. Blake Gastr., p. 409, 1889. 



Lucapinella limatula Pilsbry, in Tryon, Man. xii. p. 198, pi. 36, f. 13, pi. 61, iigs. 6, 7, 8, 9. 

 May 1891. 



