Natural History of British Animals. 235 



tenlacula ranged around it. Small individuals, possessing ap- 

 parently the same structure as the larger ones, occur around the 

 bases of the latter. The vesicles are distinctly seen even in 

 these. The Coryna is very hardy ; its tentacula scarcely contract 

 when touched ; and the body may be cUvided, and detached en- 

 tirely from its base, without the head altering its form, or the 

 tentacula shrinking. The specimens I examined were from the 

 east coast of the Island of Bute, where they were found attached 

 to fuci, near low water-mai-k *. 



Valkeria, (Flem. Brit. An. 550.) ; V. glomerata, C. (Plate II., 

 Fig. 1. & 2). — Stem simple, slightly branched, partly creeping, 

 partly erect. Cells ovate, lengthened, with the mouths slightly 

 compressed quadrangular ly ; scattered over the stem in irregular 

 groups. Before the polype is evolved, the cell is closed at the 

 distal extremity by a conical covering (This is represented at 

 a a, Fig. 2.) Polypi with ten tentacula, finely ciliated. They 

 extend considerably beyond the mouths of the cells, to the mar- 

 gins of which each is attached by a membrane, which is protrud- 

 ed before the tentacula, when the polype is about to expand it- 

 self. When alarmed, it contracts very rapidly. 



Found attached to the stems of Fucus nodosus, in small pools, 

 at low water, near Leith. 



Note — Notwithstanding the number of the tentacula, I have 

 placed this species in the genus Valkeria, on account of its 

 agreement in habit and general character with the V. uva and 

 cuscuta. Perhaps it ought to form a separate genus. The 

 termination of a branch, with a group of cells, is represented in 

 Plate II, Fig. 1. of its natural size, and considerably magnified 

 in Fig. 2. The protuberances on the stem, marked b b, seem 

 to be the rudiments of future cells. 



Halichondria suberica, (Flem. Brit. An. 522.) Plate II, 

 Fig. 3, 4, & 5. I found two specimens of this sponge in Rothe- 

 say Bay, attached to old shells of Turritella tcrebra, each con- 

 taining within its ma.ss a spiral cavity of two turns, continuous 

 with that of the shell. The cavity enlarges towards its mouth, 



• This beautiful animal Professor Jameson met with among the Shetland 

 Islands. — Vide Wcrncrian Memoirs, vol. i. p. 505. 



q2 



