232 HALECIIDyE. 



sides incurved, expanding gradually towards the top, 

 with a patulous opening and an everted rim ; a single 

 TENTACULOID ORGAN on the stem a little below the 

 calyclc, and many distributed 011 the creeping stolon; 

 GONOTHECJE ovate, ringed transversely, with a wide tubu- 

 lar neck, subpedicellate, borne on the creeping stolon; 

 POLYPITES very tall when extended, the inferior portion 

 of the body clavate, the oral funnel-shaped ; tentacles 

 about 18, a brownish cluster of thread-cells between 

 each pair, on the connecting web. 

 Height about inch. 



THE branching of O. mirabilis is very slight and simple. 

 It forms small tufts, bearing three or four polypites ; the 

 extremity of the stem often runs out into a long, filamen- 

 tary offshoot, with short lateral branches. 



The polypite, when fully extended, is a singularly 

 beautiful object, imitating to some extent the form of a 

 tall and graceful candelabrum ; only the base of the 

 body is within the calycle. The web that unites the lower 

 portion of the tentacles forms a rather deep cup* surround- 

 ing the proboscis, with the batteries of thread-cells, which 

 glitter against a dark ground, set round the outside of it. 

 These intertentacular thread-cells are similar to those 

 which thickly cover the capitulum of the snake-like organs. 

 They emit a very long thread with a barbed base ; these 

 slender filaments may be seen cast forth beyond the ten- 

 tacles and intermingling with them, and must constitute 

 an effective auxiliary force for the capture of prey. The 

 arms are held alternately elevated and depressed. 



When kept in confinement the tentacles are soon 

 thrown back, drooping listlessly downwards, and the pro- 



* There is a conspicuous opake-while collar within this cup, al the base 

 of the anus. 



