﻿SPH.ERIUM.— Plate I. 



finely grooved, deep greenish-brown, within 



fleshy in the middle, bine towards the margin ; 



umboes rather central, obtuse, dorsal margin 



sloped at both sides. 

 Lamarck. Anim. s. Vert. 

 Cydas corneum. Dilwyn. 

 Hah. Great Britain. Europe generally. 



Species 5. (/, a, h, PI. V. Mus. Brit.) 



Sph.£RIUM lacustke. Sjj/i. tesfd ovatd, inflata, pallida, 

 Icevi, latere aniico hreviori, latere postico vi.n 

 oblique truncato, margins dornali subdecUvi. 



The pale SPHiERiDM. Shell ovate, inflated, pale, 

 smooth, anterior side shorter ; posterior side, 

 scarcely obliquely truncated, dorsal margin a 

 little sloped. 



Dkapaenadd. Hist. Moll. p. 130, PI. X. f. 0, 7. 



Cijdas ovale. Ferrussac. 



Cijdas pallidum. Gray. 



Hah. Regent's Park, London. France. 



Sow 

 Hah. 



vSpecies G. (Mus. Sowerby.) 

 ..ERii'M LKNTiCDLARis. 8ph. testd sabcoiiqri-e!<.td, 



politd, hreviter ocali, corneo-grUescenti, altd ; 



umbonibus stibcentralihus, margine dorsali utrinqiii' 



dedive, margine podico ohtiisissime truncato. 

 i LENTICULAR Sphj:eidm. Shell rather compressed, 



polished, shortlj- oval, greyish horn, high ; 



umboes rather central, dorsal margin sloped on 



each side ; posterior margin very obtusely 



truncated. 



iKBY. 



— ? We have no locality for this rather 

 peculiar shell. 



Species 7. (Mus. Brit.) 



Sl'H.ERlUJI SULCATUM. Sjdl. tigtd „IJlg,ld, i'lljlatd, sab- 



rhotiihoided, validi siilrafd, fiisn,..,i,bviridi, tra),>'- 

 versd; umhonihus subccntralibus, pronrinentihus; 

 margine dorsali utrintpie pauIo dedive, marginihus 

 lateralihus obliqve suhtruiicati.i, marg'ne ventraJi 

 rediilsciilo. 

 The GROOVED Sph.erium. Shell large, inflated, 

 rhomboidal, strongly snlcated, greenish brown, 

 transverse ; umboes nearly central, prominent ; 

 dorsal margin a little sloped on each side ; 



lateral margins a little truncated obliquely; 



ventral margin rather straight. 

 Lamarck. Anim. s. Vert. 

 Hah. Massachusetts. 



Species 8. (Mus. Hanley.) 



Sph^RIUM Indicum. Sph. trstd subrutundd, pallidd, 

 liHvi, altiusculd; umbonibus subcentralibus, pro- 

 minentibus, rotwidis, margine venirali convexo, 

 margine dorsali jMstice redii)sculo. 



The Indian Sph^rium. Shell rather rounded, pale, 

 smooth, rather high ; umboes rather central, 

 prominent, rounded, ventral margin convex, 

 dorsal margin rather straight posteriorly. 



Deshayes. Proe. Zool. Soc. 1854, p. 342. 



Hah. Loodianah, India. 



Species 9. (Mus. Brit.) 



Sphj:RIDM ScaldUN'UM. Sph. tfxtd oblongo-subqnadratd, 

 pallide aurantid, tiimidd, Icevigatd, subinwquila- 

 lerali, latere antico breviori; umbonibus promi- 

 ■tientibus; margine dorsali postico rectiuMulo, 

 marijiiie venfrali rectiiisculo. 



Scaldi's Sph^rium. Shell oblong-subquadi'ate, pale 

 orange, tumid, smooth, rather inequilateral, an- 

 terior side shorter ; umboes prominent, poslero- 

 dorsal margin rather straight, ventral margin 

 rather straight. 



NoRMAND. Notas Cycl. Nord. p. 3, 1854. 



Hah. Europe. 



Species 10. (Mus. Brit.) 



SpHyERIUM caltculathj!. sph. testa subquadratd, 

 complanatd, comp)res.'id, inmquilaterali ; latere 

 antico hreviori, oblique subtruncato, margine dor- 

 sali redo, brevi ; latere postico expanso; oblique 

 qvadrato, margine dorsali recto, paulo elevato; 

 umbonihns acutis, tuhercido cahjcifonni desiuenti. 



The capped Sph.brium. Shell rather square, flattened, 

 compressed, inequilateral ; anterior side shorter, 

 obliquely subtruncated, dorsal margin straight, 

 short ; posterior side expanded, obliquely square, 

 dorsal margin straight, a little raised ; umboes 

 sharp, ending in a little cuji-sliaped tnbercle. 



Draparnaud. Moll. PL X. f. 14, 15. 



Huh. Europe. 



Quite distinct from Cijdas lacustris of the same 



author. 



