308 ELEMENTS OF COMPARATIVE ZOOLOGY. 



production, etc. 

 from the colony. 



Usually one or more of these is absent 

 The most familiar of the Siphonophores 



FIG. 140. Diagram of a Siphonophore. 

 c, covering scale ; d, digestive sac ; 

 f, float ; m, mouth of feeding indi- 

 vidual ; r, reproductive bell; s, 

 swimming-bell; t, tentacle. 



FIG. 141. Portuguese man-of-war 

 (Physalia). After Agassiz. 



is the "Portuguese man-of-war," which occasionally drifts 

 on our shores. In this beautifully-colored species the float 

 is large and the swimming-bells are absent. 



