506 FLUSTRELLIDvE. 



larva (Cyphonautes) , 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 corniculatum of Sraitt, from Spitz- 

 bergen, is a second species of the present genus. 



FLUSTRELLA HISPIDA, Fabricius. 

 Plate LXXII. figs. 1-5. 



FLCSTRA HISPIDA, Fabricius, Faun. Groenl. 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 UISPIDUM, Johnst. B. Z. ed. 2, 363, pi. Ixvi. fig. 5 : Smitt, 



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

 FLUSTRA SPONGIOSA, Templeton, Loud. Mag. N. H. ix. 469. 

 MKMBRANIPORA SPONGIOSA, Johnst. B. Z. ed. 1, 282. 

 FLUSTRA CABNOSA, 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 HISPIDA, Gray, B.M. Rad. 108 : Eedfern, Quart. Journ. Micr. 



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



Arsskrift, 1863, 12 (sep.). 



Zoarium a rather thick brown crust, the surface rendered 

 hispid by numerous reddish-brown corneous spines. 

 Zooecia elongate-ovate or subquadrangular, or six-sided, 



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

 the transparent case by which 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 larvae. (See Aim. N. II. for November 1851, 

 (ser. 2, vol. viii.) pi. xiv. figs. 1, 2.) 



