THE COAST OF CALIFORNIA. 15 



The number of radial tubes among the metluste of the 

 Anthomedusse is generally constant, four or nuiltii)les of 

 four. The majority of genera have four of these tubes ; 

 some have ei<>ht and more, while but one or two are said 

 to have six. Four is the constant numl)er which prevails 

 even through the Siphonophora and its multiple is an al- 

 most constant feature among the so-called Discophora. 

 The genera with six radial tubes are marked ones as in- 

 troducing a new unit in an almost universally quadruple 

 series. 



The other structural features of Microcampana are dif- 

 ferent from those of any hydroid genus with six radial 

 tul)es, while the character of the tentacle is very excep- 

 tional. 



The bell is asymmetrical, conical, smooth, transparent, 

 with a long conical apical protuberance. Clusters of ne- 

 matocysts are irregularly scattered upon its outer surface. 

 The apical protuberance of the bell recalls a similar ap- 

 pendage in Saphenia, Stomatoca and Amphinema. 



The bell has six radial tuUes, a marginal vessel, and an 

 apical tube or funiculus ending blindly in the apical prom- 

 inence. The radial tubes are narrow and simple without 

 lateral branches. 



The marginal appendages to the rim of the bell are of 

 two kinds. At the peripheral end of live of the radial 

 tubes there are simple projections or protuberances, which 

 are densely pigmented. From the extremity of the re- 

 maining radial tube there hangs a club-shaped tentacle 

 which recalls in structure the tentacles of the genus Di- 

 purena. This appendage is clavate, stiff, enlarged into 

 a globular body at its free extremity. At its base, where 

 it is attached to the bell margin, there is a tentacular 

 bulb which resembles the stumpy appendages of the other 

 five tubes. The club-shaped appendage swings freely 



