﻿PLA.NORBIS.— Plate XIII. 



Species 110. (Mus. Brit.) 



Planoebis lenticularis. Pla. testa parvd, suhcom- 

 2}i'essd, fused, Icevi, dextrali; spird planiusauld, 

 anfradlbus trilms, convexiusculis, ultimo superne 

 angidato, carinato, injra anguslaid ; disco inferiori 

 profunde umhilicato; aperturd suhtrigoiid, ad 

 atiguluin externum sahacwiunatd. 



The lenticulau Planorbis. Shell small, rather flat, 

 brown, smooth, dextral ; spire rather flattened, 

 whorls three, rather convex, last angular above, 

 keeled, narrow below ; lower disc deeply umbi- 

 licated ; aperture subtrigonal, acuminated at the 

 outer angle. 



Hartman ? Adams, Genera of Jlollusca. 



Flanorhis opercularis. Gould. 



Hah. Sacramento River. 



SowERBT. Genera of Recent and Fossil Shells. 

 Huh. Guadaloupe. 



Species 111. (Fig. a, h, Mus. Brit.) 



Planorbis Guadalodpensis. Pla. testa .-i/'/(/.s7/(///, rom. 

 pressd, latd, fulvd, politd ; spird co'iicani, anjnicti- 

 bus senif, aomiexiiisctilis ; ultimo anfractu inagito, 

 supra suturam elevatd, turn declivi, infra latins- 

 culd ; disco inferiori convexo ; aperturd suhirigond, 

 margine inferiori ad atifractum ultimum pro- 

 ducto. 



The Gdadaloupe Planorbis. Shell sinistral, com- 

 pressed, broad, fulvous, polished ; spire concave, 

 whorls six, convex ; last whorl large, raised 

 above the snture, then sloped, rather broad be- 

 low ; lower disc convex ; aperture rather tri- 

 gonnl, lower matgiu produced on the body 

 whorl. 



Species 11-2. (Mns. Brit.) 



Planorbis dilatatos. Pla. testd albd, dextrali, sujieme 

 ovgidatd, infra angulum angustatd, disco inferiori 

 profii'iide excavato, aperturd ma-timd, trigond, 

 giqieriir comphnuitd, wfrd acwminatd. 



The dilated Planorbis. Shell white, dextral, an- 

 gular above, narrow below the angle, lower disc 

 deeply excavated, aperture very large, trigonal, 

 flattened above ; acuminated below. 



Pfeiefer. AIoll. de I'Allemagne, Vol. II. p. 165. 



ILih. ^Massachusetts. 



The last whorl suddenly expamls towards the 



moutli, which is the large.st of the whole genu."* in 



proportiwn to the body whorl. 



Species 113. (Mus. Brit.) 



Planorbis Swinhoei. Pla. testd siibdepressd, semipel- 

 lucidd, fused, suhconico-irimcatd, superne planu- 

 latd, medio subangidatim productd, infra planu- 

 latd; disco inferiori anguste nmbihcato ; ap&rturd 

 subtrigond, margine externo prodiicto, margine 

 superior i fte,i;uosim dejyressd. 



Swinhoe's Planorbis. Shell subdcpressed, semij)el- 

 lucid, brown, rather angularly truncated, flat- 

 tened above, somewhat angularly produced in the 

 middle, flattened below, lower disc narrowly um- 

 bilicated ; aperture rather trigonal, outer margin 

 produced; upper margin flexuously 



H. Adams. Proc. Zool. Soc. 



Hah. Isl. Formosa. 



