52 THE NAUTILUS. 



Helix Carpenteri is a species which from its native peculiarities is 

 is "svell adapted to inhabit tlie desert regions, and continue to exist 

 where the majority of our helicoid shells would be unable to retain 

 a foothold. 



Dr. Bowers writes rue that he " found these shells on the south side 

 of the valley among granite talus, and nowhere else, and these in a 

 fossil state," but judging from the appearance of some of the speci- 

 mens it is probable that living shells may still be found in the 

 vicinity ; but whether this variety represents the ancestral form of 

 the more recent type, or is a local deviation arising from pecularities 

 of environment cannot be satisfactorily determined without further 

 investigation of the locality. 



While writing the above I found some other species of semi-fossil 

 mollusca, which were collected in the same locality some time ago, 

 by an enthusiastic young naturalist, whom I have since learned, lost 

 his life in the desert regions of Lower California, thus adding one 

 more martyr to the cause of science. He sent these shells to me for 

 determination, and not having heard from him since, I will give 

 the determination of their species in a future number of the 

 Nautilus. 



PRELIMINARY NOTICES OF NEW AMNIC0LID.5:. 



BY H. A. PILSBRY. 



Cochliopa Tryoniana Pilsbry. 



A more depressed shell than C. RoivelU (the only other described 

 species), broader, with the base rounded, not carinated around the 

 umbilicus. Whorls 3^, convex, rather obsoletely spirally striated ; 

 color greenish-gray. Umbilicus minute. Aperture very oblique. 



Alt. 3?, diam. 4 mill. ; oblique alt. of aperture 2t, width 2 mill. 



Habitat, Polvon, Nicaragua. 



Amnicola Sheldoni Pilsbry. 



Shell rather elongated, solid, thick, light gray ; subimperfbrate. 

 Whorls four to five, slightly convex, somewhat flattened above, 

 lightly striate transversely ; slightly impressed below the shallow 

 sutures. Apex obtuse. Ajierture small, ovate, slightly narrowed 



