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. 42(>. — 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 hippopus to designate a wide-spread Mediterranean 



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



(Fewkes.; 



