FAMILY LYMN^ID^ 7I 



Range. — Manitoba to New England, New Mexico, and Georgia. 



Lake Superior! Lake Winnipeg (Rich) ! 



This attractive species is readily recognized by its Succinea-WX'i'i. form 

 and fine spiral sculpture. The synonvmy as given by Binney and others 

 seems to need revision. I am not of the opinion that this form belongs 

 properly in the Radix group, as it has several features in common 

 with Stagnicola., notwithstanding the form of the shell. An anatomi- 

 cal examination will decide the question. 



Lymnaea (Radix) randolphi F. C. Baker, Plate i, figs. 3, 4. 

 I.yninaa randolphi Baker, Nautilus, xviii, No. 6, p. 63, Oct., 1904. 



Shell large, thin, angulate or subangulate at the shoulder ; constricted 

 strongly at the suture, narrowly and deeply umbilicate, whorls about 

 four, rapidly increasing in size but frequently decollate ; when entire 

 the spire is less in length than the aperture but the proportion is vari- 

 able ; in conformity with the sutural constriction the posterior angle of 

 the aperture is usually somewhat narrow, the apertural margin con- 

 tinuous over the body, with a narrow deep umbilicus over which the 

 pillar lip may be reflected. The pillar is sometimes slightly sinuous 

 but not plicate, the surface may be smooth and polished, malleated, 

 spirally threaded or minutely reticulated by axial and spiral lines. 

 The periostracum is pale, but usually has a dark line at resting stages ; 

 the outer lip is hardly expanded though often a little patulous in front ; 

 it is never internally thickened. Measurements : 



Range. — Lake near Cosmos River, north of the Kowak River, 

 Alaska, about N. Lat. 68° (Lieutenant Stoney) ! Kowak River, Alaska 

 (Stoney) ! Nushagak River, Alaska ! Lake Marsh! and Lake Linde- 

 man, Yukon Territorj- ! Lake La Hoche, British Columbia ! East of 

 Fort Colville, Wash. ! 



This form is very recognizable, with its angular whorls and dceplv 

 constricted suture. A specimen from near Fort Colville, figured by 

 Binney as a possible variety of L. sumassi Baird {op. ci't., p. 43, fig. 

 5S) , may prove a feebly angulated and unusually short spired specimen 

 of this species. I have received it under the names ampla. stimassz, etc., 

 from several Pacific Coast correspondents, and a large nutnber of mostly 

 defective specimens were obtained by the expedition into nortliwc^tern 



