Notes on certain Terrestrial MoUusca. 



167 



The general contour of P, Californica and P. Powellii, is 

 similar, but the latter has a slightly more tapering spire, and 

 its aperture is smaller in proportion than in the former. The 



Fi0. 11. 



EiG, 12. 



P. Kowellii Ne\^c.. 



P, Californica EowelL 



aperture of P. Bowellii is narrower at the base, and the basal 

 tooth is longer and sharper than in P. Californica. The latter 

 has elevated rib-lit:e striae, which are peculiar to it, and is the 

 only prominent character distinguishing it from P. decora 

 Gould. 



Succinea ISillimaiii, nov. sp. 



T. oblongo-ovata, tenuis, ruguloso-striata, iiiti(iula, albida ? ; spira 

 brevis, acuta ; anfr. 3 convexi ; sutura impressa ; apertura obliqua, elon- 

 gato-ovata, superne angulata, basi effusa ; columella leviter arcuata, 

 superne filariter incrassata. 



Shell oblong-ovate, thin, coarsely striate, shining, whitish ? 

 spire short, acute; whorls 3, convex; suture 

 impressed ; aperture oblique, elongate-oval, 

 angular above, effuse at the base ; columella 

 slightly arcuate, with a thread-like thickening 

 above. 

 Long. 20, diam. 8J- mill. ; Ap. 13 mill, longa, 

 medio 6 lata ; anfr. ult. 17i mill, longus. 



Fig. 13. 



Succinea Sillimani, 

 Bland. 



Hahitat. — Humboldt Lake, Nevada. A single example 

 without epidermis, but fresh in appearance, was found and sent 



