﻿PLANORBIS.— Plate VIII. 



Species 65. (Fig. .r, 6, Mus. Brit.) 



PlanoRBIS GRACILENTDS. Pla. testa ilc.etrali, albldii, 

 oj)aed ; spird planiuscidil ; anfractihus qiiinis, 

 apicalibus angustis, externis latiuscuUs, ad aper- 

 turam subdilatatis ; aitvrtnrd .^nhtrignnd ; disco 

 inferiori late uinlilicatn. 



The slender Planorbis. Shell de.-itral, whitish, 

 opaque; spire rather flat; whorls five, apical 

 narrow, external rather broad ; a little dilated 

 at the aperture ; aperture a little trigonal ; lower 

 disc broadly umbilicated. 



Gould ? MS. Brit. Mus. 



Hah. Colorado Desert. 



Species GO. (Fig. .;. 6, Mns. Brit.) 



PlANOEBIS DEPEESSISSIMIS, I'hi. Irsid r,,„qih:t ludd, ciddi: 



depressd, ^je'?'"'"'"', j>"llidr ,■,>,-, ir,i, s/i/zv/' .-ompla- 

 natd; anfractihus <,/,!, „ is, t.^uuihus. I,„l!- .-resct-M- 

 tihus, supernli ad marijiiifui amli' (iminlatis ; discn 

 inferior! plarmlato ; aprrtm-a lal.-ralitrr elmn/ata. 

 avgido cxternn acuta. 



The very flat Planorbis. Shell flattened, uuich de- 

 pressed, pellucid, pale horn, spire flattened; 

 whorls seven, thin, slowly increased, at the 

 margin above sharply angular ; lower disc flat- 

 tened ; aperture laterally lengthened, outer 

 angle sharp. 



MoRiCAND ? MS. Mu.s. Brit. 



Hoi. ? 



The whorls arc perhaps the flattest of any in the 



genus. 



Species G". (Fig. a, h, Mus. Brit.) 



Planorbis subanoulatus. Pla. tcsfd jmllide corned, 



t,n„idi,',sr„1d, si„ist,-r,!i : aifrarlihiis tritnis, rapide 



rrrsrrii/iluK, siinrnii r, m rr.r is. I a / i ii sr a I is ; disCO 



-■"i" 



/-(/,. 



,fri.n-i s„h„,nj>dato, 



cnvato ; aperturd superne latera.litrr proditctd, 



infra versus medium inclinato. 

 The subangular Planorbis. Shell pale, horny, rather 



tumid, sinistral whorls three, quickly increased; 



convex, i-ather broad ; upper disc broad, convex, 



lower rather angular, excavated ; aperture latere 



ally produced above, inclined towards the middle 



below. 

 Philippi. Eneycl. 2, PL XXI., f. <",. 

 Hah. Malta, Sicily. 



Species 68. (Mus. Brit.) 

 Planorbis seeiceus. Pla. testa sinistrnli. tmuiilias. 

 ridd, pallide fused, spird angusti- inf until, nhi/d ,• 

 aifractibus quinis, superne angnlatis, a mjiistalis ; 

 discn inferiori excavato, anfractihus rotimdis ,- 

 aiiertiird snMrigond, infra expansd, rotundd. 

 'I'm: i:hicory Planorbis. Shell sinistral, rather 

 tumid, pale brown, spire narrowly funnelled ; 

 whorls five, angular above, narrow ; lower disc 

 excavated, whorls rounded ; aperture subtri- 

 gonal, expanded, rounded below. 

 DuNKER. Pro<_'. Zool. Soc. 1848, 42. 



Hah. ? 



Diff'ering from Planarhis conimutatit.s in the pro- 

 portionate narrowness of the whorls, and the funnel- 

 shaped excavation is more ananlar, distinct, and 

 narrow. 



