PLEUROBRANCHUS. 559 



form approaches much nearer to the shape of the preceding 

 species, but the shell is devoid of any similar radiating 

 indentation of surface. 



The animal grows to a considerable size. It is of a 

 general oval shape. The tentacles and oral veil are pale, 

 the latter produced at the angles. The dorsal disk is 

 papillated and of a rusty brown hue, but varies greatly in 

 intensity of colour. The branchial plume is yellowish and 

 pale. The margins of the foot are expanded and pale, 

 except at the edge, where they are bordered with tawny. 



This fine species has been taken at low water at various 

 localities on the Devonshire coast, where it was first noticed 

 by Montagu. Mr. Barlee has found it at Arran and Bir- 

 terbuy in Ireland, and Mr. Humphreys at Cork. Our 

 figures of it and of its congener are taken from some 

 admirable original drawings by our eminent and accom- 

 plished friend Mr. Alder. 



P. PLUMULA, Montagu. 



Small, testaceous, narrow ; apex coiled. 



Plate CXIV. F. fig. 6, 7, and (Animal), Plate X. X. fig. 1. 



Bulla plumula, Mont. Test. Brit. p. 214, pi. 15, f. 9 ; vign. 2, f. 5, animal — 

 MATONand Rack. Trans. Linn. Soc. vol. viii. p. 123. — Turt. 

 Conch. Diction, p. 25. — Dillw. Recent Shells, vol. i. p. 478. — 

 Wood, Index Testaceolog. pi. 18, f. 16. — Gratkl. Sur las Bull, 

 (and in Bull. Lin. Bordeaux), p. 10. 

 Bertliella porosa, Blainv. Man. Malac. pi. 43, f. 1. 



Pleurohranchus plumulut Fleming, Brit. Animals, p. 291. — Johnston, Mag. 

 Nat. Hist. vol. vii. p. 348, f. 46 ; Berwick. Club, 

 vol. ii. p. 27, with animal. — Brit. Marine Conch, 

 p. 132. — Brown, Illust. Conch. G. B. p. 62, pi. 2, 

 f. 14, 15. 



The shield of this rare species is much smaller than in 

 vnembranaceai and although thin and semitransparent, is 



