BRITISH TUNICATA. 



scarcely half the size of the thorax, kidney-shaped. 

 Post-abdomen fusiform, joined to the abdomen by a 

 slender thread-like peduncle which is continued below 

 and either terminates abruptly or is connected by 

 branches with other individuals. 



Diameter of the masses from a quarter of an inch to 

 about an inch (6-25 mm.). 



Hab. On the under side of stones between tide- 

 marks. [Attached to stones, in crevices of rocks, etc., 

 at low water-mark (GocJcs).~\ 



ENGLAND. Cullercoats, Northumb. (Alder Sf Han- 

 cock). Bambrough, Northumb.; Douglas, Isle of Man 

 (Alder). [Gwyllyn-vase, Swanpool, Pennance, etc., 

 Falmoutli, Cornwall (Cod's, 1849).] 



WALES. Menai Straits, Anglesey (Alder). 



CHANNEL ISLANDS. Guernsey (Alder). 



First record. Forbes & Hanley, 1848; [coll. Alder, 

 1847.] 



FIG. 89. A branchial aperture of Polycliuum aurantium in a state of 

 dilatation, x about 3o. (M. Edwards, pi. iii, f . 4 a.) 



2. Polyclinum succineum Alder. 



(Plate LI, fig. 6.) 



Poli/clinum succineum ALDER in Ann. Nat. Hist. (3) XI 

 [1863], p. 169 ; [NORMAN in Eep. Brit. Assoc. for 1868 

 (1869), pp. 257, 303]. 



Colony sub-globose, a little depressed, very trans- 

 parent, amber-coloured, attached by a broad base ; 

 the surface slightly lobated. Individuals dispersed 

 over the surface without apparent order, forming 

 numerous systems each with a prominent funnel-shaped 

 common excretory orifice of great transparency (PL 

 LI, fig. 6). Branchial aperture 6-lobed; atrial with 



