OBELIA GELATINOSA. 57 



uppermost, and the bell turned inside out. 

 When in that condition, it is highly suggestive 

 of an umbrella in a like predicament. 



The specific name is very appropriate, 

 signifying bent like the knee. It may be called 

 the zig-zag hydroid, a term which equally well 

 describes it. The hydroid throws up zig-zag 

 stems, and from each bend rises a short 

 ringed shoot bearing a polypite, the receptacle 

 of which is somewhat triangular with a plain 

 rim. The capsules which are large, and urn- 

 shaped, are borne in the axils of the shoots. 

 This species is very common and overruns 

 many objects. 



Obelia gelatinosa, Pallas. (Plate II.) 



1 specimen in liquid. 



specimen This is one of the tallest and most 

 23. conspicuous of the shore* hydroids. 



The stem is compound, some five or six inches 

 in height, with branches arranged in whorls 

 around the axis ; these, again, throw out 

 secondary shoots. The polypary is ringed 

 just above the branching, and the receptacles 



* i.e. Growing on rocks, stones, &c, between tide-marks. 



