SETOSELLA VULNERATA. 181 



character, I am unable to assent to this view. The remark- 

 able structure of the zoarium in Cupularia, and its free 

 condition when adult, are points of much systematic value ; 

 and to these must he added the great development of the 

 vibracula, and their (probable) assumption of a locomotive 

 function"^. 



SeTOSELLA VULNERATA, Busk. 

 Plate XXI. fig. 7. 



MembraniporA VULNERATA, Busk, Quart. Journ. Micr. Sc. viii. (1860), 124, 

 pi. XXV. fig. 3: Norman, Shetl. Dredging Rep., Brit. Assoc. 

 Rep. 1867, 305. 



Setosella VULNERATA, Hinclcs, Ann. & Mag. N. H. for Dec. 1877. 



Zocecia somewhat pyriform or oval ; margin slightly raised, 

 smooth, unarmed ; orifice small, arched above, the lower 

 lip a little curved outwards ; lamina minutely granular, 

 rising rather abruptly towards the mouth, usually with 

 a narrow, slit-like fissure, slightly curved, on each side, 

 a little below the orifice. Long and slender vibracula 

 distributed over the colony on distinct intercellular 

 areas, one immediately above each cell. Ocecia? 



Colonies forming very small, white, subcircular patches. 



Range of Variation. There are sometimes considerable 

 differences in the size of the cells within the limits of the 

 same colony. The shape varies from suboval to pyriform ; 

 the cells are generally much narrowed towards the orifice, 

 and expand to a moderate degree beloAV. The lateral 

 fissures in the lamina are occasionally wanting. 



* Mr. Busk informs me {in /iff.) that bis conjecture respecting the loco- 

 motive i'uuctiou of the vibracula amongst the family of Seleiiariada (to 

 which Cuptdaria belongs) has been confirmed by actual observation. 



