CCELENTERATA : HYDROZOA. 



99 



colour and semi-transparent, and it floats at the surface of the 

 sea, with its vertical crest exposed to the wind as a saiL 



Fig. 20. — Physopkorida. a Portuguese man-of-war (/'^^ja/w f<^rtV7//«f), showing the 

 fusiform float and the polypites and tentacles (after Huxley) ; b VeUUa vulgaris 

 (after Gosse). 



Divisions of the Physophoeid^. — (After Huxley.) 



Fam. I. Apolemiadce. — Hydrosoma with nectocalyces and hydrophyllia, 

 the latter united with the other organs into groups which are arranged at 

 considerable intervals along the ccenosarc. Coenosarc filiform. Pneuma- 

 tocyst small. 



Fam. II. StephanomiadiF. — Hydrosoma with nectocalyces and hydro- 

 phyllia, the latter arranged with the other organs in a continuous series. 

 Coenosarc filiform. Pneumatocyst small. 



Fam. HI. Physophoriadce. — Hydrosoma with nectocalyces, but without 

 hydrophyllia. Distal end of the filiform ccenosarc dilated. Pneumatocyst 

 small. 



Fam. IV. Athorybida. — Hydrosoma without nectocalyces, but with 

 hydrophyllia. Pneumatocyst occupying almost the whole of the globular 

 coenosarc. 



Fam. V. Rhizophysiadce. — Hydrosoma without either nectocalyces or 

 hydrophyllia. Coenosarc filiform. Pneumatocyst small. 

 6 



