134 



THREE CRUISES OF THE " BLAKE. 



the absence of nectocalyces, whose function is in part taken by 

 the covering scales. They are capable of a slight motion on 

 their attachment, and by this movement an active propulsion is 

 produced. The float is large, and 

 the stem very much reduced in 

 length. The genus is interesting 

 from its resemblance to a young 



Fig. 429. Gleba hippopus. 



(Fewkes.) 



stage of Agalma having 

 no nectocalyces, in which 

 a similar circle of covering 

 scales is found. A new 

 species, A.formosa, from 

 the Florida Keys, has been 

 added to the medusae of 

 the Gulf Stream. 



The close resemblance of the swimming-bells of one genus of 

 the floatless siphonophores to a horse's hoof suggested the 

 name of Jiippopus to designate a wide-spread Mediterranean 

 species (Gleba hippopus, Fig. 429) found in the Gulf Stream 



Fig-. 428. Ag-alma Okenii. \. ( Fewkes. ) 



