﻿P L A N K P. T S. 



Spt'fk-s On. (Fig-, a, h, Mus. Brit.) 



Planokbis Sl'ENCERl. Pill, testa pared, flavido-fmcd, 

 suhdeiyressd, sinistrali, hvvigatd; spird compta- 

 natd, j)(in'((., anfractlhus tpiaternis, ultimo latius- 

 rido, ^H/ii'nii' cmu-'-.ru'isculo, ad marginem ohscu- 

 rU'-ihH- ii'iijiditto, infra antjuhtm angustatd ; difco 

 inferiori e.rciivato ; (tpirtin'i s.niil iinnri. 



Si'KNOER's Plasokuis. SIk U small, yellowish-brown, 

 subdepressed, sinistral, snionth ; spire flattened, 

 ■small, wliorls four, last rather broad, rather 

 convex above, very obscurely angular at the 

 margin, narrowed below ; lower disc excavated ; 

 aperture semilunar. 



Allex ? MS. Brit. Mus. 



ILih. Portugal. 



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



Pl.ANiiKRis NiTliiruis, ria. testa teiiui, pellncidd, pal- 

 lidissimi; cortin'i, Itiniiilii'isruld ; sjiird planimcidd, 

 medio excai-ald, ,<ii'jiisl,l, mifradihts quaternis, 

 utrinfpie tuvuitiiif:i:iilis ; disco inferiori excavate; 

 aperturd supernc Idtn, irfra angustato. 



The neat little Pl.^noreis. Shell thin, pellucid, 

 very pale horn, rather tumid : spire rather flat, 

 a little excavated in the middle, narrow ; whorls 

 four, rather tumid on each side ; lower disc ex- 

 cavated ; aperture broad above, naiTOw below. 



UraKER. Proc. Zool. Soc. 1848, p. 40. 



Hub. Malacca. 



Species 62. (Fig. a, h, Mus. Brit.) 

 Pl.wjorius ungulatus. Pla. tcsfd laid, depressd, 

 arC'Uatd, corneo-ruhesctnti ; spjird vix conve.rd, 

 anfradihiis septenis, lente cresceniilus, siiperne 

 angulatis, suhcarinatis ; disco inferioii convexo ; 

 aperturd ohliqnd, sttperiw acute angulatd, pro.- 

 dactd. 

 The tai.oned Planorhis. Shc41 broad, depressed. 



arched, reddi.sh-horny, spire hardly convex : 

 whorls seven, slowly increased, angular above, 

 somewhat keeled, lower disc convex ; aperture 

 oblique, sharply angular above, produced. 



Chitty ? JIS. Brit. Mus. 



Hah. Jamaica. 



The sharp prominent angle in the margin of the 



whorls, with the slightly arched under surface, gives 



the profile of this shell a talon-like ajspearance. 



Species 63. (Fig. o, b, Mus. Brit.) 



PlANORBIS COMMUTATUS. Pla. tesld siltistndi, tliniidd. 

 ventncosd, palUde fused, tenui ; sju'ril infundilja- 

 latd ; anfractibus quiiiis, angulatis, svperiie ait- 

 gustatis, infra ventricosis, rotundis ; disco -inferiori 

 profundi', umbilicato, anfractu, apicali obtectu ; 

 aperturd rotundo-subtrigond. 



The changed Planorbis. Shell sinistral, tumid, 

 ventricose, pale brown ; spire funnelled, whorls 

 five, angular, narrow, ventricose, rounded below ; 

 lower disc deeply umbilicated, apical whorl hid- 

 den ; aperture roundly subtrigonal. 



DuNKER ? MS. Brit. Mus. 



Hab. N. America. 



Species G4. (Fig. a, b, Mus. Brit.) 



Planorbis Aecticus. Pla. testa pared, pallide fulvd, 

 suhdepressd ; spird parvd, pauV) cvcavatd ; an- 

 fractibus trihus, rotundis, rapid!- crescentihus, 

 tumidinscidis, disco inferiuri Inti: imihUicato, aper- 

 turd rotunda. 



The Arctic Planorbis. Shell small, pale fulvous, 

 rather depressed ; spire small, a little excavated ; 

 whorls three, rounded, quickly increasing, rather 

 tumid, lower disc broadly umbilicated ; aperture 

 rounded. 



Beck ? MS. Mus. Brit, 



Ilab. Greenland. 



