OPERCULARELLA. 193 



lowed and reflexed lips,, reaching almost to the margin 

 of the umbrella ; RADIATING CANALS 80-90 ; MARGINAL 

 TENTACLES white, attenuated, with small bulbs at the 

 base, extremely numerous (as many as 400 iiithe adult); 

 LITHOCYSTS with from two to five refractile spherules. 



THE polypites have only been observed in their earliest 

 stages of growth, and we are ignorant what the perfect 

 form may be. Dr. Wright, having procured specimens of 

 the sexual zooid (the JEquorea vitrina, Gosse), succeeded 

 in hatching the ova, and tracing the development of the 

 planules into extremely minute polypites, which he could 

 not distinguish from the hydroid phase of Campanulina 

 acuminata. They were quite invisible, however, to the 

 naked eye, and in too immature a state to allow of satis- 

 factory examination. 



The goiiozooid attains a very large size, being sometimes 

 as much as about six inches and a half in diameter. Mr. 

 Gosse's specimens were much smaller, and only partially 

 developed. The oral lobes and the marginal tentacles, 

 with their attendant lithocysts, in the examples which 

 came under his notice, were much less numerous than in 

 the adult. The latter numbered more than 200, and the 

 former about 20 ; while in the older individuals examined 

 by Wright there were no less than 400 tentacles and 40 

 lobes. The umbrella is perfectly translucent, and the 

 radiating canals are described as resembling "bands of 

 frosted or ground glass upon a body of clear glass." 



Hub. Ilfracombe (Gosse) : Scotland (T. S. W.). 



Genus OPERCULARELLA, Hincks. 



Der. A diminutive form of Opercularia, from Operculum, a lid. 

 GENERIC CHARACTER. Stem simple or branching, rooted 

 by a thread-like stolon ; hydrothecce ovato- conic, with a cleft 

 border, the segments of which conrcrt/e to form <ni o 



o 



