162 THE CHICAGO ACADEMY OF SCIENCES. 



TYPE: Smithsonian Institution, one broken specimen (No. 5541) ; 

 two specimens (Binney's two original specimens) No. 8571. 



ANIMAL, JAW, RADULA AND GENITALIA: Unknown. 



RANGE : Idaho to Washington, north to central California. Pacific 

 coast drainage of the Columbian and Calif ornian regions, and the 

 Transition and Upper Austral Life zones. 



RECORDS. 



UNITED STATES. 



CALIFORNIA: Antioch, Contra Costa Co. (Cooper). 



IDAHO: Near Challis, Custer Co. (Dall; Merriam; Stearns). 



WASHINGTON: Lake Vancouver, Clarke Co. (Gould; Wilkes). 



GEOLOGICAL DISTRIBUTION : Unknown. 



ECOLOGY: Not recorded. 



REMARKS : Lcpida appears to be a rare species, and has not been 

 seen by the writer in any collection excepting that of the Smithsonian 

 Institution, where Gould's original specimens are deposited. As sug- 

 gested by Cooper (Pr. Cal. Acad., IV, p. 51), it is very like a diminu- 

 tive stagnalis and the figures published are strongly suggestive of the 

 immature state of that species. The record from Meech's Lake, On- 

 tario (Trans. Ott. Nat. Field Club, I. p. 58), though said to have been 

 verified by Tryon, is erroneous, the specimens being young stagnalis. 

 A good series of this species from the original locality might prove 

 it to be the young or a diminutive variety of stagnalis. Additional 

 information is greatly needed. Gould's observation concerning its re- 

 semblance to pallida and desidiosa (obrussa) is not borne out by an 

 examination of his type specimens. 



Genus PSEUDOSUCCINEA Baker, 1908. 



Pseudosuccinea BAKER, Science, n. s., XXVII, p. 943, June, 1908. 



Radix of authors. 



TYPE: Lymncea columella Say. 



SHELL: Of medium size, succineif orm ; spire generally short and 

 somewhat dome-shaped ; last whorl very large, expanded ; axis gyrate 

 and imperf orate ; columellar plait not well marked ; outer lip sharp. 

 (Plate XVIII, fig. 5.) 



JAW : Wide and low, with a bluntly rounded median projection. 

 (Plate VI, fig. C.) 



RADULA: With tricuspid lateral teeth; marginals serrated. 



GENITALIA : Prostate very small, cylindrical, with rounded ter- 

 mination ; penis-sac retractors two in number ; penis retractors inserted 

 in posterior penis-sac retractor; penis short and thick, less than one- 

 half the length of the penis-sac ; penis nerve inserted in head of penis. 

 (Plate X, fig. B.) 



