]32 THE OCEANIC HYDROZOA. 



to the ends of special stalks. In this region the somatic cavity, which has the form of a wide 

 canal, is excentric, being situated nearer the convex side of the coenosarc. In many places 

 it gives off csecal diverticula, which pass at right angles into the substance of the thicker wall. 



The hepatic striae are eight to twelve or more in number, and are situated in the 

 proximal third of the digestive cavity of the polypite. 



The stems of the tentacles give off, on one side, branches to which the sacculi are 

 attached. 



The hydrophyllia have a triangular form, their prolonged proximal ends or apices being 

 attached to the peduncles of the polypites, while the basal or distal ends are divided into 

 three points. They are slightly concave on the inner side, slightly convex externally, where 

 they present a sliglit median ridge. 



The hydrocysts are of two kinds — simple, attached immediately to the coenosarc ; and 

 double, one large and one small, attached by a long common peduncle to the coenosarc. A 

 single and double hydrocyst are commonly associated in pairs. Each hydrocyst has a slender 

 simple tentacle. 



The androphores and gynophores are usually, if not always, attached to the base of tlie 

 double hydrocyst.' 



Two to four androphores and a larger number of gynophores are usually associated 

 together. In structure they appear, from Kolliker's description, very closely to resemble those 

 of Slejjhanomia amphitridis. 



' Whence these should probably be regarded as gonoblastidia. 



