THYLACIUM STLYANI. 137 



2. Thylacium Sylvani V. Gams. 

 (Plate XLVI, figs. 9-11.) 



Thijlacium Sylvani VICTOR CARUS in Proc. Ashmol. Soc. II 

 [(1851), p. 268]. 



Bod)/ more or less globular or oblong-ovate, united 

 in clusters to a common base, of a dark, dusky, a sh- 

 red colour, lighter when young. Apertures rather 

 distant, 011 short conical papilla?, paler than the body. 

 Test (PL XLYI, figs. 9-11) coriaceous, rough; (in 

 specimen sent by the Rev. D. Ashford) reddish brown, 

 rose-coloured when young. Mantle bright crimson or 

 scarlet. 



Height from a quarter to three-quarters of an inch. 



Hab. On the under-surface of overhanging rocks 

 near low-water mark (Carus). 



ENGLAND. Meledyon, White Isle, behind Sampson 

 Island, Scilly Isles ; gregarious in immense numbers 

 (Carus). 



First record. Carus, 1850. 



2. Thylacium Normani Alder. 

 (Plate XLV, figs. 3-5.) 



Thylacium Normani ALDER in Ann. Nat. Hist. (3) XI [1863], 

 p. 167 ; [NORMAN in Rep. Brit, Assoc. for- 1867 (1868), p. 

 439] . 



Body subclavate, rounded above and contracted a 

 little below r , reddish, firmly fixed in groups to a 

 common fleshy base. Apertures rather large and pro- 

 minent, set considerably apart at the upper end, 

 quadrate, or nearly circular when expanded, some- 

 times appearing as a single slit when closed. Test 

 (PI. XLV, figs. 3-5) strongly wrinkled or sub-tuber- 

 culated, rather smoother near the apertures. Ten tac-nlar 

 filaments linear, very slender. Branchial sac with two 

 or three folds (?) on each side. 



