148 



depahtment of tbe i^atal service 



great contraction and extension, hence the body or the 

 tentacles may be long and slender or short and stout. 



Gonosome. Sporosacs borne on special generative 

 zooids, usually smaller than the nutritive, without 

 tentacles or mouth; miale and female zooids in different 

 colonies. 



Other zooids. Defensive zooids are present, long, 

 slender, often doubled; on themselves to form spirals, 

 without tentacles^ but, well supplied with batteries of 

 nematocysts. 



Sensory zooids, longer even then the defensive 

 zooids, without tentacles or nematocysts. 



No. 17. 

 Ilydractinia echinata. 



Family MYRIOTHELID^. 



" Polypites solitary, with very numerous, minute, capitate tentacula scattered 

 over the body " (Hincks) . 



Genus Myriothela. 



Trophosome. " Polypites solitary, cylindrical, terminating above in a conical 

 proboscis, springing from an adherent base, which is clothed with a chitinous poly- 

 pary; tentacles very small, capitate, covering the greater portion of the body" 

 (Hincks). 



Gonosome. " Gonophores borne on coryniform processes, clustering around the 

 base of the polypites, and containing fixed sporosacs" (Hincks). 



MyriotJwla plirygia (Fabricius). 



Trophosome. " Polypite cylindrical, very extensile; tentacles extremely numer- 

 ous and closely set, covering about three-fourths of the body, with a reddish-brown 

 spot on the capitulum; the basal portion of the body 

 minutely speckled with white and crowded with the 

 processes bearing the gonophores, which are slender, 

 pointed above with a few wart-like tentacles on the 

 upper portion ; the adherent base massive, of a dark 

 brown colour, sending out a few tubular and root-like 

 prolongations" (Hincks). 



Gonosome. " Gonophores produced a little below 

 the tentacles, subsessile, globular, when mature of a 

 very large size and a pink colour ; embryo actinif orm " 

 (Hincks). 



No. 18. 

 Myriothela plirygia (after Hincks) 



Family PENNARID.F. 



Trophosome. Hydranths with a proximal whorl of long filiform tentacles 

 around the body, and several capitate tentacles scattered distally. 



Gonosome. Gonophores producing free medusae. 



Genus Acaulis. 



Trophosome. Hydranth stemless, sub-cylindrical; tentacles of proximal set fili- 

 form; tentacles of distal set, short, strongly capitate, numerous, scattered over the 

 body of the hydranth. (From Stimpson's description.) 



Gonosome. Gonophores scattered, sessile on the body of the hydranth betxpeen 

 the proximal and distal set of tentacles. (From Stimpson's description.) 



