148 LAND AND FRESH- WATER SHELLS OF N. A. [PART II, 



— DeKay, N. Y. Moll. 13 (1643).— MuLLER, Syn. Test. 1834 prom. 

 p. 2 (1836). 



In the plate referred to, Prof. Halderaan calls this species a^ 

 Vellettia. In the text he placed it in Ancylus. I have copied 

 his figure. 



Fossil Species of Acroloxus. 



Dr. Meek gives me the following name of a fossil species : — 



Acroloxus minutux, Meek & Hayden MSS. {Anctjlus minutus, Proc. Acad. 

 185G, p. 120.) 



Gi;]VDLACIIIA, Pfeiffek. 



Tentacles — ? Mantle — ? Foot — ? 



Shell thin, ancyliform, non-spiral, obliquely conical ; apex in- 

 clined backwards, basal side two-thirds closed with a flat, hori- 

 zontal lamina ; aperture anterior, horizontal, semicircular ; peri- 

 treme continuous, simple, entire. 



Jaw — ? 



Lingual membrane (of G. californica) with a small bicuspid 



Fig. 249. , 



Lingual dentition of Gundlachia californica, 



central, and 16, oblique, tricuspid lateral teeth. 



This is a strictly American genus as far as is now known, 

 species having been described from the West Indies and Central 

 America. In the Boston Proc. 18()3, 249, will be found an ex- 

 tremely interesting account by Dr. Stimpson of the growth of 

 the animal. 



