254 Z. ASCIDIOIDA. Valkeria. 



the stones in them" — " Among many other marine substances re- 

 ceived fresh from the sea, in September 1 753, this object happened 

 to present itself under ray magnifying- glasses ; when, to my surprise, 

 I found those grape -like bodies were a cluster of polypes, each hav- 

 ing eight claws or tentacula, very lively, extending themselves about 

 in pursuit of prey ; and upon their dying, the animals contracted 

 themselves into their vesicles, which closed at the top : What we 

 discover as a spot, is only the intestines of the polype with its food 

 in it." Ellis. 



3. V. IMBRICATA, cells in dense clusters irregularly scattered 

 on the jiolypidom. Adams. 



Plate xxix. Fig. 5, G. 

 Sertularia imbricata, Adams in Lin. Trans, v. xi. pi. 2. fig. 3 — 11. Turt. 



Gmel. iv. 683. Turt. Br. Faun. 216. Steio. Elem. ii. 450. Thomp. 



Zool. 111. 94. pi. I. fig. 1-4 Valkeria glomerata, Coldstream in Edin. 



New Pbil. Journ. ix. 235. pi. 2. fig- 1,2: and in Edin. Journ. Nat. and 



Geog. So. iii. 53 Serialaria imbricata et S. verticillata, Templeton, 



in Mag. Nat. Hist. ix. 467, fig- 66. 

 Hab. Parasitical on various littoral Fuci. On Fucus nodosus 

 in Milford haven, Adams. In small pools, at low-water, near Leith, 

 Dr Coldstream. " On the Fuci and Confervas, on the shore of 

 Belfast Lough, near White-House Point," Templeton. In the harbour 

 of Cove, one of the most obvious and common species, J. Thompson, 

 " Stem simple, slightly branched, partly creeping, pai-tly erect : cells 

 ovate, lengthened, with the mouths slightly compressed quadrangu- 

 larly, scattered over the stem in irregular groups. Before the polype is 

 evolved, the cell is closed at the distal extremity by a conical covering. 

 Polypi with ten tentacula, finely ciliated : they extend considerably 

 beyond the mouths of the cells, to the margins of which each is at- 

 tached by a membrane, which is protruded before the tentacula when 

 the polype is about to expand itself. When alarmed, it contracts 

 very rapidly." Dr Coldstream. — According to Mr Thompson this 

 species creeps over the surface of the Fuci by means of its tubular 

 ramifying roots, and throws off numerous flaccid irregularly branched 

 shoots to the length of from one inch to one and a half or more, 

 often so densely clustered as entirely to cover the plant on which it 

 grows. 



4. V. PUSTULOSA, vesicles clustered, unilateral. Ellis. 



Plate xxix. Fig. 7-9. 

 Dichotomous tubular Coralline, Ellis, Corall. 54. pi. xxvii. fig. h. B — 

 Sertularia pustulosa, Ellis and Soland. Zooph. 54. Turt. Gmel. iv. 

 680. Bosc, Vers, iii. 113- Steic. Elem. ii. 444. Turt. Brit. Faun. 



