CYCLAS. 
253 
The shell is rather solld^ opaque within ; the um™ 
bones paler and often circumscribed with a dark line ; 
length height thickness 6~ lines, 
115. 2. Cyclas cornea. Horny Cycle.— Shell sub- 
orbicular^ globose^ thin^ very finely striated ; 
umbones blunt ; ligament inconspicuous, (t, 
1. f. 2.) 
Tellina cornea. Linn^ S. N. i. 1120. ; Linn. Trans, viii. 59. ; 
Don. D. S. t. 96. — Sphserium corneum. Scopol. Int. H. N, 
398.; Bourg. Speer. 21. — -Cyclas scaldiana. Norm. Cycl. 
5. t. 5. f. 12. — Sphaerium scaldianum. Norm. Cycl. t. L 
— Sphaerium citrinum. Norm. Cycl. — Nuxuigella. Humph. 
Cat. 59. — Tellina rivalis. Muller.^ Verm. Hist. ii. 202. — 
Cardiurn corneum. Pulteney.i Dorset, Mont. T. B. 86, 
— Cardiurn nux. Da Costa., B. S. — Cyclas cornea. Lam. 
Hist. V. 558. ; Pfeiffer., 120. t. 5. f. 12. ; Nihon., Moll. Suec. 
96.; Turton^ Biv. 248. t. 11. f. 14., Man. ed. 1. 13. f. 2.; 
Flem. B. A. 452. ; Jenyns., 1. c. 8. ; Leach., Syn. Moll. 290. ; 
Dupuy., Moll. Franc. 666. t. 29. f. 4. ; Forhes and Hanley., 
B. M. ii. 113. t. 37. f. 3. 456. — Cyclas stagnicola. Leach., 
MSS. Brit. Mus.., Syn. Moll. 291. — Cyclas cornea /3. 
Jenyns., 1. c. 8. — Cyclas rivalis. Drap. Moll. 129. — Cyclas 
nucleus. Stud. Verz. 93. — Cyclas flavescens. Macgilliv. 
Moll. Aherd. 246. — Cycl. isocardioides. Norm. — Cyclas 
citrina. Brown, III. C. iS2. t. 39. f. 37. 
Yar. 1. stagnicola. Shell subglobose, rather flattened on the 
basal edge ; umbones tumid, pellucid, very prominent : 
Tellina stagnicola. Shepp. Linn. Trans, xix. 150. 
Yar. 2. gibbosa. Shell very gibbous ; margin very blunt. 
Yar. 3. compressa. Shell rather compressed, the margin meet- 
ing at an acute angle: Cyclas alata. Leach, Syn. Moll. 
291. (?) 
Yar. 4. minor. Small, nearly globular. 
Inhab. turf-pits, fens of Cambridgeshire.' 
Animal white ; the siphons rather elongate, pale 
flesh-coloured, upper rather tapering, lower cylin- 
drical, truncated ; foot, when expanded, rather 
longer than the shell. 
