80 [April 



Description of New Fresh xcaier Shells from CaHfornia. 



By Isaac Lea. 



Familj- LYMN^ANA. 

 Genus Pompholyx. 

 Testa rotundo-gibbosa, subtus retrorsa, superne planulata, non umbilicata; 

 spira depressa, apertura amplissima, subrotuada, effusa ; labro acuto ; labio 

 incrassato, planulato ; operculum nullum. 



PoMPHOLYX EFFUSA. Testa parva, striata, rotundo-gibbosa, subtenul, efFusa, 

 luteo-cornea; anfractibus trinis, superne planulatis, inferne convexis ; apertura 

 subrotunda, dilatata, intus albida, maculata. 



Hah. Sacramento River, California. Dr. Trask. 



Melania Shastaensis. Testa striata, subcjlindracea, subtenui, tenebroso- 

 cornea, fasciata ; spira elevata ad apice plicata ; suturis valde impressis ; an- 

 fractibus convexis ; apertura parva, ovata, intus albida; columella laevi, incur vata 

 et recurvata. 



Uah. Shasta and Scott Rivers, California. Dr. Trask. 



Melania niguixa. Testa lasvi, parva, conica, sublenui, nigricanti, polita ; 

 spira subelevata ; suturis impressis ; anfractibus regulariter convexis ; apertura 

 parva, ovata, superne angulata', intus tenebroso-purpurea; columella iucurva, 

 purpurea. 



Uah. Clear Creek, Shasta County, California. Dr. Trask. 



Physa triticea. Testa subfusiformi, pellucida, polita, rufo-castanea ; spira 

 brevi, subacuta ; suturis subimpressis ; anfractibus quaternis, subconstrictis ; 

 apertura elongata, intus lineata. 



Hah. Shasta County, California. Dr. Trask. 



Planorbis Traskii. Testa magna, tenebroso-cornea, subcylindracea, minute, 

 crebre et regulariter striata, superne late et profunditer umbilicata ; inferne 

 magis excavata ; anfractibus quinis, superne acute carinata ad peripheriam, in- 

 ferne obtuse carinata ; apertura auriculseformi. 



Hah. Kern Lake, Tulan County, California. Dr. Trask. 



Lymn>ea proxima. Testa acuto-conica, subtenui, crebre et irregulariter striata, 

 cornea, minute perforata; spira subelevata, ad apicem acuminata ; suturis valde 

 impressis; anfractibus septenis, convexis; apertura subiuflata, subelliptica, intus 

 fasciata, columella paulo plicata. 



Hah. Arroya San Antonio, California. Dr. Trask. 



Ancylus patelloides. Testa magna, crassa, elliptica, maculata, oblique 

 conica ; striis crebris, minutis ; apice submediali. 

 Hah. Sacramento River, California. Dr. Trask. 



The following species, heretofore described, were part of the " envoi " made 

 by Dr. Trask. 



Margaritana margaridfera^ Lea. 

 Alas.falcata, Gould. 

 Alas. Yitho'vsis, Trask. 



From Klamath and Yuba Rivers. 



I received specimens of this shell from Prof. Xuttall in 1837, brought by him 

 from Columbia River. I thought then, and I still think, there were not characters 

 sufficiently distinct in them to form a new species. The observations published 

 at the time (Tran. Am. Phil. Soc. v. 6, p. 97) are still in accordance with my 

 opinions, after having had many specimens from various localities under exami- 

 nation The purple in the nacre is stronger than any I have seen from other 

 localities, but this with the other differences would not I think warrant its being 

 considered more than a mere variety of M. margaritifera. 



