CYCLAS. 
257 
b. Cardinal teeth single {rarely two divergent) ; shell 
thin^ subquadrigonal ; umhones prominent 
118 . 5. Cyclas lacustris. Capped Cycle. ^ — Shell 
rather rhombic, compressed, thin, yellowish 
white, diaphanous ; umbones prominent, 
rather acute, and tuberculose ; ligament 
inconspicuous, (t. 1. f. 3.) 
Cardium lacustre. Mont. T. B. 89. — Tellina lacustris. Linn, 
Trans, vii. 60. ; Turton., C. D. 180. — Cyclas calyculata. 
Drap, 130. t. 10. f. 13, 14. ; Lam. Hist. v. 559. ; Pfeiffer.^ 
122. t. 5. f. 17, 18.; Nilson, 99. ; Turton, Man. ed. 1. 14. 
f. 3. ; Dupuy., Moll. Franc. 672. t. 24. f. 8. ; Forhes and 
Hanley.^ B. M. ii. 118. t. 37. f. 7., t. O. f. 7. — Cyclas lacustris, 
Turton, Biv, 249. t. 11. f. 18.; LeacJi^ Syn. Moll. 289. — 
Tellina tuberculata. Alton., Syst 4. t. 1. f. 1. — Cyclas tu- 
berculata. Klees., 45. • — Spbaerium lacustre. Bourg. Sphcer. 
36. — Spheerium Brochonianum. Bourg. Sphcer. 50. t. 3. f. 
5. — Cyclas consobrina. Feruss. in Blainv. D. S. N. xii.. 
279. — Sphserium Desbayesianum. Bourg. Amoen. 6.^ — SpbsB- 
rium ovale. Bourg. Sphcer. 31. t. 4. f. 6. 10. — Cyclas la- 
custris. Forhes and Hanley., B. M. ii. 118. 
Young, the apex of the shell large relatively to the size of the 
specimen. 
Inhab. rivers. 
Yar. 1., shell orbicular, less compressed, subdiaphanous, red- 
dish brown. ^ 
Cyclas lacustris. Alder., Cat. i. 40., Brit. Mus. —■ Cyclas 
calyculata jS. Jenyns^ Monog. 11. 
Inhab. ponds. 
Yar. 2., shell orbicular, rhombic, rather ventricose, subdiapha- 
nous, reddish ; umbones less prominent, blackish. 
Cyclas stagnicola. Leach, MSS. fide Lam. — Cyclas caly- 
culata, var. 2. Lam. Hist. v. 559. — Cyclas calyculata y. 
Jenyns., Monog. 11. 
Inhab. north of England. {Jenyns^ 
Animal white ; siphons white, elongate. 
This species, when in confinement, shows more 
activity than (7. cornea ; they sometimes remain at 
s 
