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 



length. The genus is 



from its resemblance to a young 



in 



interesting 



Fig. 420. 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 liippopus to designate a wide-spread Mediterranean 

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



Fig. 428. Agalraa Okenii. \. (Fewkes.) 



