194 PROCEEDINGS OF THE MALACO LOGICAL SOCIETY. 



Eocene : Tnickee Lake beds, Nevada. 



Silver Peak llaiige, Nevada : Near coal-mine (type) (H. AV. Turner) ; 

 same locality (S. A. Knapp) ; 1 mile south-east of coal-mine 

 (H. W. Turner); H miles south-east of coal-mine (H. W. Turner). 



All the material of this species examined is rather distorted bv 

 crushinjr, but the series examined is sufficiently large to determine 

 the specific characters. Named after Mr. H. W. Turner, formerly of 

 the United States Geological Survey, who obtained most of the 

 material while mapping the Silver Peak llange. 



ViviPARus Washingtonfanus, Arnold & Hannibal, n.sp. 

 PI. VIII, Pig. 32. 



Shell small, seldom over 20mm. in altitude, similar to V. sub- 

 piirpureus of the Gulf States, but with a decidedly elevated spire, 

 but slightly impressed sutures, and more slender nuclear whorls. 

 Whorls appressed, decidedly sloping, and distinctly sub-carinate at 

 the peri])hery ; habitat apparently lacustrine. 



Altitude 20, breadth 15, altitude of aperture 12 mm. 



Eocene : Local freshwater beds in Tejon formation, AVashington. 



Little Ealls, Washington : Bluffs along Olequa Creek above shoals 

 2 miles north of town (type); at slioals Ih miles north of town; 

 bend a half-mile south of town (H. Hannibal). 



Genus Idiopoma (Pilsbry). 

 Paludina (sp.), Lamarck, 1822 {P. Bengalensis, Lam.); Vivipara 

 {Idiopoma) (sp.), Pilsbry, 1901 ( F. (/.) Ilenzadensis, Pilsbry), 

 Type, Vivipara {Idiopoma) Henzadensis^ Pilsbry. 



Sub-genus Cipangopaltjdina, n. sub-gen. 



Type, Paludina malleata, lleeve. 



Sub-genus Idiopoma, s.s. Shell of moderate size, averaging 25 mm. 

 in altitude, elevated-conic, sub-perforate, whorls appressed and 

 tapering, peripherally carinate from early development stages, the 

 carina becoming sub-obsolete on the body-whorl, apex elevated and 

 prominent, aperture ovate and slightly retracted below ; habitat 

 lakes, streams, and marshes. 



Sub-genuS Cipanf/opaludina. Shell similar to Idiopoma, but conic- 

 turbinate, perforate, early whorls appressed and peripherally carinate, 

 later whorls ecarinate, and inflated with impressed sutures, aperture 

 ovate; Idiopoma stage passed during adolescence ; habitat similar. 



Idiopoma Japonica (von Martens). 

 Paludina Japonica, von Martens, 1860. 



Shell large, spire broad and strongly elevated, with a small 

 prominent apex, sutures but little impressed, whorls deep and 

 i)i'oadl}- appressed, mai'ked by spiral striae which have a tendency 

 to be accentuated into carinations in forms from alkali waters, 

 ])eripheral carina very pronounced in young stages, and becoming 

 sub-obsolete only on the last half-whorl, axis sub-perforate, aperture 

 liigher than broad ; habitat quiet streams and marshy situations. 



Japan : introduced in Coast llange System. 



