281 



flesh-coloured, upper rather tapering, lower cylindri- 

 cal, truncated; foot, when expanded, rather longer 

 than the shell. 



114. 3. CYCLAS lacustris. Capped Cycle, (t 1. f. 3.) 

 Shell rather rhombic, compressed, thin, yellowish 

 white, diaphanous; umbones prominent, rather 

 acute, and tuberculose ; ligament inconspicuous. 



Cardium lacustre. Mont. T. B. 89. 



Tellina lacustris. Linn. Trans, vii. 60. ; Turton, 



a D. iso. 



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. 



Cyclas lacustris. Turton, Biv. 249. t. 11. f. 18. 



Young. The apex of the shell large relatively to 

 the size of the specimen. 



Inhab. rivers. 



Var. 1. Shell orbicular, less compressed, subdia- 

 phanous, reddish brown. 



Cyclas lacustris. Alder, Cat. i. 40., Brit. Mus. 



calyculata /3. Jenyns,\. c. 11. 



Inhab. ponds. 



Var. 2. Shell orbicular, rhombic, rather ventricose, 

 subdiaphanous, reddish; umbones less promi- 

 nent, blackish. 



Cyclas stagnicola. Leach, MSS.fide Lam. 



calyculata, var. 2. Lam. Hist. v. 559. 



y. Jenyns, 1. c. 11. 



Inhab. north of England. (Jenyns.) 



Animal white ; siphons white, elongate. 



This species, when in confinement, shows more 

 activity than C. cornea ; they sometimes remain at 



