156 Biyney on Terrestrial Mollusks. 



In order to make the following a complete monograph 

 of American Avriculacea, I have copied from the Terres- 

 trial Mollnsks the entire description of the few species 

 mentioned in that work. 



So few persons are interested in this family of Mollusks, 

 and the extent of our coast is so great, the following must 

 be considered as a very imperfect attempt at a monograph 

 of the American species of the family. 



Pfeifl'er subdivides the family into three subfamilies : — 

 Otinea, Melampea, and Auricnlea, respectively analogous 

 to the Ancylea, a subfamily of Limneacea, — to the true 

 Limneacea, and to the Aciciilacea. The first subfamily is 

 not represented in this country. 



SUBFAMILY MELAMPEA. 



This subfamily is distinguished by an acute, simple 

 peristome. The aperture is generally armed with tooth- 

 like laminae. The animals of all our species are subaquatic, 

 living in close proximity to salt or brackish water. 



H. and A. Adams give the name of MelampincE to this 

 subdivision. In America it has been noticed as a family 

 by Stimpson, (Shells of N. E.), who calls it Melampidw^ 

 and includes one species and one genus which Pfeiffer 

 refers to a separate subdivision of the family. 



Genus MELAMPUS Moxtfort. 

 The characteristics of this genus are the same as those 

 already given for the subfamily. 



It is an inhabitant of every quarter of the globe. 



MELAMPUS BIDENTATIS Say. 

 Plate LXXV. Figuhe 23. 



T. imperforata, elliptico-ovata, tcnuiuscula, nitens, (aut corrosa,) lineis 

 minutis transversis, et rugulis longitudinalibus notata ; cornea, aut griseo- 

 bninnoa, iiitcnlum fasciis 4 rufis, angustis, oiiiaulata ; sutuj-a distincla; 

 spira brevis, obtiisa; anir. 6-7, supori planiu:>(iili, iiltiimis | long. aHjuans, 



