﻿PLAN E B I S. 



it'so-J. (Fii,'. a, h, Mus. Brit.) 



KKMATOIDKS. I'lit. I' ali'i .inlii-n 



s»pni tmncalo-conU;',, 



■ ■arnioUi, ad medium wnbdiro nifund;i,i,lif„niii 

 rxcnralu ; s/iin! drjin-ssii, anfracfihiif: ijnalcnn';:, 

 nithnn m<ui,iu. 



The .siiEAK-snAi'F.i. I'lamiuhis. Shell a little com- 

 pri'sseil, whili.sh, ti-uncato-conical above, flat- 

 tened below, keeled, hollowed in the middle, 

 with a funnel-shaped umbilicus ; spire depressed, 

 whorls four, last large. 



D'OuiiiG.NY. Voy. Anier. Merid. PI. XLY., f. 1-4. 



TT'ih. S. Amei-ica. 



Species "lo. (ilus. Brit.j 



I'LAXOUIUS LUCUiUS. Pla. iestd comprvssd, Sfmipel- 

 liicidd, Jaivi, ob.'^curc castaiieo-corned ; spird de- 

 pre^sd, anfractibus quinis sitbplanulatis, ultimo 

 coiivexo, infra ■medium subangulato ; disco iiifenori 

 concavo, angustiiisculo, aperturd subquadratd, infra 

 latiiisi'uld. 



The lucid Pi^anorbis. Shell compressed, semipel- 

 lucid, smooth, chestnut-horn ; spire depressed, 

 whorls five, rather flat, last convex, rather 

 angular below the middle ; lower disc concave, 

 rather narrow, aperture rather square, rather 

 broad below. 



l'nii,ii'Pi ? irS. Brit. Mus. 



Ilab. ■ r 



Species 54. (Fig. a, b, M\is. Brit.) 

 Planorbis septemgyratus. Pla. testa vaUVe depressd, 

 utrinque coiicaru. fanrn.siibviridi, anfractibus sep. 

 tenis, anr/nstissiiiii.--, altiino angusto, aperturd 



])ressed, concave on both sides, brownish-green, 

 whorls seven, ver}- narrow, last narrow ; aper- 

 ture small, obliquely ovate. 



Zeigler ? MS. Brit. Mus. 



Hab. Vienna. 



A renuirkably thin, wafer-like shell. 



Species 55. (Fig. a, b, Mus. Sowerby.) 

 Planorbis Beckianus. Pla. testa tumidd, siitistrd, 

 livviijdtd, corned, medio nnfractunm ct itifra rres- 



/(,//-■■?, spir,; drpr.'.s,;, niifnvllhas ./in./m,;^. ^iipra 

 si,l„r.ni, ,'l,r„h\; r^^hnidi,, iillinK. ninn„i.>, rnilri- 

 c.n, n,t„U,, infra lati i,.n,la, aprrt.nl ,na.,,nl: 

 disrt) iiiferiiiri profundi' e.rcavato, anfractu, apirali 

 nbtiu-ln. 



Beck's Planorhis. Shell tumid, sinistral, smooth, 

 horn, chestnut at the middle of the whorls 

 and below ; spire depressed, whorls four, raised 

 above suture, rounded, last large, venti'icose, 

 rounded, rather broad below ; aperture large, 

 lower disc deeply excavated, apical whorl 

 hidden. 



DuNKEE ? Ad. Gen. of Sh, 



Hab. Y 



Little diff'ering from Planorbis corneus. Ijut with 



the whorls more uniformly rounded than in that 



somewhat variable species. 



parvc 



obli 



The seven-whokled Plan 



Shell 



Species 56. (Fig. a, b, 5Ius. Brit.) 

 Planorbis pallidus. Pla. testa iumidiiwr.idd, h&vi, 

 pallide corned, utrinque siihcomplanatd ; spird 

 angiistatd, anfractibus quaternis, rapidh crescenti- 

 biis. ultimo lafiiisculo, svpemedeclivi, infra medium 

 iiijliil.i. disrn iiferiuri subcomplanato ; aperturd 

 obli'iio' suboratd, manjine superiori siniwfivi pro- 

 ducto, depresso. 



