266 
PISIDIAD^. 
122 , 3. PisiDiUM pusillum. Minute Pera. — Shell 
orbicular, ovate, rather compressed, very 
finely striated, scarcely inequilateral; um- 
bones rather prominent, acute, (t. 1. f. 7.) 
Tellina pusilla. Turton^ C, Diet. 167. — Cyclas pusilla. 
Turton, Biv. 251. t. 11. f. 16, 17., Man. ed. 1. 16. f. 7. — 
Cyclas fontinalis. Nilson^ 101.; Drap. 130. t. 10. f. 8. 11. 
• — Cyclas gibba. Alder^ Cat. 41. — Euglesia Henslowiana. 
Leach., MSS. Brit. Mus., Syn. Moll. 291. — Pisidium pusil- 
lum. Jenyns., Monog. 14. t. 20. f. 4, 6. ; Moq. Tand. M. 
F. ii. 587. t. 52. f. 38 — 42. ; Forbes and Hanley., B. M. 
ii. 123. t. 37. f. 11., t. O. f. 9. — Pisidium fontinale. Pfeiffer ^ 
D. M. i. 125. t. 5. f. 15, 16. 
Inhab. ponds. 
b. Shell inequilateral, 
123. 4. Pisidium pulchellum. Beautiful Pera. — 
Shell oblique-ovate, ventricose, deeply 
striated ; umbones rather blunt, simple, 
(t. 12. f. 151.) 
Pisidium pulchellum. Jenyns., Monog. 18. t. 21. f. 1.; Forbes 
and Hardey., B. M. ii. 128. t. 27. f. 12, 13. —Pisidium caje- 
tanum ^ pulchellum. Moq. Tand. M. F. ii. 584. t. 52. f. 24. 
28. — Cardium amnicum jun. Montag. T. B. 88. 
Yar. 1., smaller; shell thin, finely striated, umbones rather 
acute. 
Pera pulchella. Leach., MSS. Cab. 'Brit. Mus.., Syn. Moll. 
292. — Pisidium fontinale. Pfeiffer. — Cyclas fontinalis. 
Brown., Edin. Journ. N. and G. Soc. i. 11. t. 11. f. 5. 7.; 
Alder., Cat. 41. — Pisidium pulchellum /3. Jenyns^ Mon. 
18. t. 21. f. 2, 3. 
Var. 2., shell obliquely oval, finely striated, compressed; mar- 
gin acute. Pisidium pulchellum y. Jenyns., Mon. 18. 
Yar. 3,, shell rather oblong, very ventricose, deeply striated ; 
edge very blunt, hinge margin nearly straight. Pisidium 
pulchellum 5. Jenyns., Mon. 18. t. 21. f. 4, 5. 
Inhab. ponds, Birkham Common, Surrey. 
Animal white ; siphon variable, conical or elon- 
gate, with an entire or lobed end. 
