188 BRITISH TUNICATA. 



Height about two-tenths of an inch. 

 Hab. Adhering to the roof and sides of caves 

 (Norman). 



CHANNEL ISLANDS. Gouliot Caves, Sark (Norman). 

 SCOTLAND. [St. Margaret's Bay, Shetland; dredged, 

 1867 (Norman).] 



First record. Alder, 1863; coll. Norman [1859]. 



[Alder (loc. cit.) says that this species " is much 

 smaller than the T. Sylvani of Carus, of a different 

 form, and appears to spread more horizontally."] 



4. Thylacium variolosum (Gaertner). 

 (Plate XL VI, figs. 12-14.) 



Distomus variolosus GAERTNER in Pallas' Spic. Zool. I, fasc. 



10 [1774], p. 40; [LAMARCK Hist. Nat. Anim. sans Yert. 



ed. 1, III (1816), p. 101, and ed. 2, III (1840), p. 498]. 

 Alcyoniiim ascidiuideN PALLAS Spic. Zool. I, fasc. 10 [1774], 



p. 40, pi. iv, ff. 7, 7a ; [GMELIN Linnasi Syst. Nat. ed. 13, 



I, pt. 6 (1791), p. 3816;] TURTON Brit.' Fauna [1807], 



p. '208. 

 \_Alcyonium distomum BRUGUIERE Hist. Nat. Yers, I (1789), 



p/23, in Encycl. Meth. ; Bosc Hist. Nat. Yers, III (1802), 



p. 132 ; LAMOURODX Polyp. Corall. flex. (1816), p. 352, 



and (transl.) Corallina (1824), p. 250.] 

 Distoma variolosum SAVIGNY Mem. Anim. sans Yert. pt. 2 



[1816], pp. 38, 178; [LAHOUROUX Exp. metli. Polyp. 



(1821), p. 73;] FORBES & HANLEY Brit. Moll. I [1848], 



p. 19. 

 [Distoma variola i 'us BLAIKVILLE Man. Malac. et Conch. 



(1825), p. 585 ; (1827), pi. Ixxxvii, f. 4.] 

 \_Botryllus variolosus DELLE CHIAJE Mem. Anim. senza Yert. 



Ill (1828), pp. 86, 94.] 



Polyzona variolosa FLEMING Brit. Anim. [1828], p. 469. 

 Thi/laciiim variegatum ALDER in Ann. Nat. Hist. (3) XI 



[1863], p. 168. 



Body (in each individual) transversely ovate, 

 depressed, doridiform, shaded with flesh-colour and 

 red. Apertures not much apart, on the upper surface, 

 the branchial rather nearer the end. Test slightly 



