38 



shells. These species are now sometimes called Try- 

 panostoma^ a Genus instituted by Dr. Lea to take tlie- 

 place of Pleurocera, Raf. The latter having priority,, 

 however, must stand. 



GENUS GONIOBASIS, Lea. 



CiO.^'IOKANIK I.IVEJ«»€K:N-S, Menke. 



Ovate oblong, smooth, moderately thick ; si")ire short,, 

 conically acute, suture slightly impressed ; whirls- 

 five to six, ratlier Hat, the last large ; aperture large, 

 elliptical. Horn color, purple within. Length, one-half 

 inch ; abundant. 



«iO.^IO«Ai!iIS l>Kl>Y<,iIS, Say. 



Oblong, conic ovate, whirls live, the last elliptical. 

 Suture well impressed ; aperture narrow ovate, acute 

 above. Color yellowish. Two rufous bands on the 

 whirls. Shorter than G. licescens. Fox and Illi- 

 nois JRitiers. 



Of more than two hundred and fifty species of Go- 

 niobasls found in American waters, the two just des- 

 cribed are all we can boast of as inhabiting this coun- 

 ty. The latter species is not so abundant here as the 

 former. All our Sirepomatidae are very hardy, liv- 

 ing some time after being removed from the water as I 

 have had occasion to notice, and differing in this res- 

 pect from the Yimparidae. They are evidently suited 

 to our northern climate. 



Note.— vaivata We find by thousands in 



the Fox and Illinois rivers, fixed to stones, etc., the 

 larva case of an insect — PJirygania. The case is built 

 of grains of sand, cemented together in the shape of 

 a valvata, for which it has been mistaken. 



