244 



CCELENTERATA. 



recall mouthless polyps and manubria; they are very sensitive and 

 mobile and, while tactile, apparently in some cases are digestive 

 organs. Latest to develop in the colony are the sexual bells. 

 They are usually brightly colored and resemble small mouthless 



B3iM 



FIG. 188. Stephalia coronata. (After Haeckel, from Lanp.) A, in section; au, canal 

 to float; fca, canal system of stalk; o, mouth ; other letters as in fig. 188. 



Anthomedusae without tentacles. They but rarely (Chrysomitra) 

 separate from the colony, but usually persist as more or less reduced 

 sporosacs. 



From this it follows that the Siphonophora afford fine examples 

 of division of labor and of the consequent polymorphism of indi- 

 viduals. This can indeed be carried so far that many convey the 

 impression of being individuals with a multiplicity of organs. The 

 Siphonophora are all marine, and occur most abundantly in trop- 

 ical seas. 



Sub Order I. PHYSOPHOR^E (Physonectee). Float present, but 

 small ; next a large series of swimming bells, and then the other members 

 of the colony. Physopliora, Agalmia, Nanomia* (fig. 189). 



Sub Order II. CALYCOPHOR^E (Calyconectse). Float lacking ; one 

 or two large swimming bells ; the other individuals in groups which fre- 

 quently separate before becoming mature, and were once regarded, under 

 the name Eudoxia, as distinct animals. Praya, Diphyes* (fig. 189), in 

 warmer seas. 



Sub Order III. CYSTOKECT^E. Float greatly enlarged ; the creno- 

 sarcal tube reduced, the individuals (no covering scales nor swimming 



