506 FLUSTRELLID^. 



larva [Cijphonautes), which is furnished with two trans- 

 parent valves, resembling in shape those of a Cypris, 

 within which the soft portions of the body are lodged. 

 As in other cases, this highly organized larva, on be- 

 coming fixed, is reduced, so far as the soft portions of its 

 structure are concerned, to an amorphous mass of proto- 

 plasm, from which the primary polypide is developed ^. 



The Alcyonidium corniculatwn of Smitt, from Spitz- 

 bergen, is a second species of the present genus. 



Flustrella nispiDA, Fabricius. 

 Plate LXXII. figs. 1-5. 



Flustra iiispida, Fabricius, Faun. Grcenl. 438: Flem. B. A. 537 : Johnston, 



Trans. Newc. Soc. ii. 266, pi. ix, fig. 7 : Blainv. Actinol. 



450: Hincks, Ann. N. H. ser. 2, viii. 357, pi. xiv. figs. 1-4. 

 Alcyonidium hispidum, Juhnst. B. Z. ed. 2, 363, pi. Ixvi. fig. 5 : Smitt, 



loc. cit. 499 and 517, pi. xii. figs. 22-27. 

 Flustra spongiosa, Templeton, Loud. Mag. N. H. ix. 469. 

 Membuanipora s,vo^GiosK,Johnst. B. Z. ed. 1, 282. 

 Flustra carnosa, Johnst. B. Z. ed. 1, 288, pi. xxxvii. fig. 5: Couch, Corn. 



Faun. iii. 125 : Hassall, Ann. N. H. vii. 369. 

 Cycloum hispidum, W. Thompson, Nat. Hist. Ireland, iv. 476. 

 Flustrella iiispida, Gray, B.M. Rad. 108 : Eedfern, Quart. Jouru. Micr. 



So. vi. 96, pi. iv. : Alder, Cat. loc. cit. 57 : Smitt, Ups. Univ. 



Arsskrift, 1863, 12 (sep.). 



Zoarinm a rather thick brown crust, the surface rendered 

 hispid by numerous reddish-brown corneous spines. 

 Zocecia elongate-ovate or subquadrangular, or six-sided. 



* In a paper published so long ago as 1851, 1 haye described and figured 

 the transparent case by wliich the larva of F. hispida is protected, showing 

 clearly (in the figure), its bivalve character, and also the mass into which 

 the larva is resolved after fixation. In the same paper an account is given 

 of the development of the polypide out of this (protoplasmic) mass. I be- 

 lieve that this is the earliest notice of the occurrence of a bivalve protective 

 case amongst the Polyzoan larva;. (See Ann. N. H. for November 1851, 

 (eor. 2, voh viii.) pi. xiv. figs. 1, 2.) 



