STYLACTIS INERMIS. 305 



The Styladh fucicoJa was discovered by Sars iu the haven of Messina, and referred by him 

 to tlie genus Podocori/ne, from which, iiowever, for reasons already mentioned, it has been found 

 necessary to separate it. The common basis, or hydrorhiza, spreads over the upper surface of 

 sea-weeds, and is described by Sars as composed of creeping, horny, branched, minute tubes, often 

 anastomosing with one another, and sending off here and there vertical, hornv, conical processes, 

 similar to those which occur in Fodocoryne carnea, but longer and more numerous. He makes 

 no allusion to the existence of a superficial naked layer of coenosarc on the hydrorhizal network, 

 as in Podocoryne and Hydractinia, and it is pretty certain that nothing of the kind exists. 



Those hydranths which are destitute of sporosacs have usually, when adult, eight tentacles, 

 which in extension are held alternately elevated and depressed. The hydranths which bear 

 sporosacs are as long as the others, and, indeed, sometimes even longer, but they are always much 

 more slender, while their tentacles are shorter and fewer, usually from two to six. 



The sporosacs are situated low down on the body, at about two fifths of its length from the 

 tentacular circlet. 



Stylacfis fiicicola has never been found, like some allied forms, on the surface of empty 

 shells, but always " on sea-weeds, especially on a little Ijrownish-red, doubly pinnated species 

 (Fucus cartilayineus, Cav., non L.) which grows in abundance on stones in the haven of Messina, 

 close to or within a foot of the sea's surface." — Sars. 



*^* 3. Stylactis ineemis, AUman. 

 Woodcut, fig. 79, page 306. 



TROPHOSOME.— Htdroriiiza destitute of spines, and formed by a layer of 

 closely approximated, tortuous, anastomosing tubes. Sterile and proliferous hydranths, 

 differing in size ; sterile hydranths about two lines in height, and with about twenty 

 tentacles, arranged in two closely set, alternating series ; proliferous hydranths about 

 half the size of the sterile ones, and with about twelve tentacles, also disposed in two 



GONOSOME. — GoNOPnoRES oval, shortly stalked, forming an irregular verticil at 

 a short distance below the proximal tentacles. 



Colour. — Hydranths and gonophores varying from a very pale pink to brownish. 



DevelojjiiH'ni of Gonosome. — April. 



Habitaf. — Spreading over the surface of sea-weeds. 



Bafhymetrical Distribution. — Region of Cystoseira. 



Locality. — Nice, Dr. du Plessis. 



