252 CYCLAD^. 



ropocis, tliey contrive to traverse the vessel from 

 side to side, as though they were crawling along a 

 solid plane. 



1. Cyclas Lam. (Cycle.) 

 Animal with suborbicular mantle produced behind 

 into two elongate contractile siphons; foot 

 tongue-shaped, very extensile ; shell suborbi- 

 cular, nearly equilateral ; hind teeth minute, one 

 in the right and two in the left valve ; lateral 

 teeth compressed, elongate, lamellar. 

 The shells are known from Fisidium by their being 

 rounder and more equilateral. 



a. Cardinal teeth two, diverging, icell developed ; shell 

 rounded, and not channelled at the umhones. 



114. 1. Cyclas rivicola. River Cycle. — Shell sub- 

 globose-ovate, ventricose, rather solid, beauti- 

 fully and closely striated, greenish brown, 

 with two or three darker bands ; edge and 

 lunule yellow ; umbones obtuse ; cardinal 

 ligament conspicuous, (t. 1. f. 1.) 



Tellina cornea, /5. Maton and Racket, Linn. Trans, viii. 59. ; 



Tiirton, Conch. Diet. 180.; Wood, t. 46. f. 3. — Cyclas 



cornea, a. Dmp. Tabl. — Cardium corneuin, var. Montagu, 



T. B. 86. — Cyclas cornea, a. Drap. Hint. Moll. 128. t. 10. 



f. 1. 3. — Cardium amnicum. Dorset. Cat. 32. — Cvclas rivicola. 



Leach, in Lam. Hist. v. 558.; Pfeiffer, L. and W. 121. t. 5. 



f. 3. 5.; Tiirton, Bivalves, 248. t. 11. f. 13. ; Fleming, Brit. 



Anim. 452. ; Jenyns, Trans. Comb. P. S. 6. ; Tiwton, Man. 



ed. 1.12. f. 1.; Leach, Si/n. Moll. 289. ; Dupuy, Moll. Franc. 



665. t. 29. f. 3. ; Forbes and Hunley, B. M. ii. 111. t. 37. 



f. 12. t. 2. f, 1. — Sphwriinn riviculum. Mont. Cut. ii. 30. — 



Spli. rivicola. Bourg. in Amden, 6. 1. ; Bourg. Mon. 12. 

 Young, compressed, pale. 

 Cyclas jequata. Sheppard, MSS. Brit. Mus. 



Inhab. rivers Thames, Trent, &c. 



