HYDROZOA. 
61 
bells, medusa-like individuals, each consisting simply of an umbrella, Case 3, 
and adapted solely for swimming ; next follows a whorl of leaf-like Upright part. 
Fig. 24. 
liydrostatica. d. Swimming-bell of the same. e. Cluster of generative 
buds (degenerate medusae) of Agalma. a , stem of colony ; a', air 
sac; m, swimming-bell; c, concavity of same; v, radial canals; 
o, orifice of umbrella ; t, covering pieces in b, tentacle-like polyps in c ; 
n, stomach ; i, tentacles ; g, generative buds. (After Gegenbaur, from 
Encyc. Britannica.) 
“ covering-pieces,” and below this a cluster of medusa-like generative 
polyps, tentacle-like polyps and short-stalked feeding polyps, each of 
