76 ANTHOZOA HYDROIDA. 



stem flattened, slightly zigzag; the branches rather close, linear, 

 alternate, bifarious, simple, or sometimes pinnated : Cells generally 

 semialternate, rather small, bellied at the base with a narrow 

 everted neck and plain aperture, so as somewhat to resemble a 

 Florence-flask : Vesicles scattered, subsessile, proportionably small, 

 smooth, ovate, with an even shortly tubulous mouth : they are pro- 

 duced principally in the winter season, when they are sometimes " in 

 such abundance as almost to cover the denticles, but placed in 

 a very regular order," Ellis ; and always on the upper edge of the 

 branch from which they originate. 



14. S. FILICULA, cells of the form of a Florence-flask, op- 

 posite, a single one in the axilla of each pinna ; vesicles pear- 

 shaped, smooth, the aperture shortly tubulous, entire. Hudson.* 



PLATE XIV. Fig. I, 1. 



Sertularia filicula pr Fern Coralline, Ellis and Soland. Zooph. 57, pi. 6, fig. c. C. 

 Turt. Brit. Faun. 215. Bees' Cyclop. Vermes, pi. 8, fig. 1. Jameson in Wern. 

 Mem. i. 564. Lam. Anim. s. Vert. ii. 119. Lamour. Cor. Flex. 188. Johnston 

 in Trans. Newc. Soc. ii. 257. Thompson in Ann. Nat. Hist. v. 250. Hassall in 

 Ann. and Mag. Nat. Hist. vii. 284. Couch Cornw. Zooph. 9 ; Corn. Faun. iii. 23. 

 S. abietina,/3, Pall. Elench. 134. Dynamena filicula, Flem. Brit. Anim. 544. 



Hob. Parasitical on sea-weeds, particularly on the entangled 

 roots of Laminaria digitata. From the observations of Mr. W. 

 Thompson, it seems to be partial to bivalve shells on the coast 

 of Ireland ; and it is also met with on Flustrae. It is not an abun- 

 dant species, but is generally distributed. 



Polypidom arising from a creeping fibre, one to four inches in 

 height, spreading bifariously, irregularly branched, slender and 

 flexible, of a straw-yellow or brownish colour, homologous through- 

 out ; the rachis zigzag, or " bent to and fro into alternate angles," 

 closely pinnated, the pinnae shooting from every bend alternately on 

 opposite sides, linear, patent, simple or composite : Cells closely set, 

 minute, giving a serrulated appearance to the ramifications of the 

 polypidom, shaped something like a Florence-flask, smooth, the 

 aperture oblique, entire : The vesicles are rarely produced, nor have 



* William Hudson, a London apothecary, elected F.R.S. in 1761 : the author of 

 the "Flora Anglica," the publication of which, in 1762, "marks the establishment of 

 Linnsean principles of Botany in England, and their application to practical use." 

 Sir. J. E. Smith. 



