//. SCYPnOZOA. 



Ml 



bells) being attached to the under side of the float. Physalia, the Portu- 

 guese man-of-war, occurs as far north as New England. It is brightly 

 colored, and, sitting high on the water, is driven about by the wind. It 

 stings very severely. 



Sub Order IV. IJISCOXANTH.E. Float a flattened disc with con- 

 centric air chambers; the manubrium projects from the centre of the lower 



Fig. 189. — American siphonophores. A, Nanoviia cara. (After A. Agassiz.) /)'. Velella 

 nteiidioiiuli^:, (After Fewkes.) C, Dlpltyes praya. (After Fewketi.) 



surface of the float. Porpita* with circular disc. Velella* (fig. 189), the 

 l)aper sailor, has a triangular 'sail' on the disc. Both arc tropical and 

 subtropical. 



Class II. Scyphozoa (Scyphomedusae). 



The Scyphozoa parallel the Ilyclrozoa in that they frequently 

 have an alternation of crenerations. The asexual generation is the 



Fio. 190. Fig. 191. 



Fig. 190.— Scyphostoma of ^!(?e((a a^(nYa. (From Korschelt-Hciiler.) /.-, perisarc cup; 

 p/3, proboscis; s, stalk; (, gastral folds; (r, ectodermal funnels. 



l'"iG. 191. — Section of Scyphostoma. (From Hatscliek.) gr, t^astric pouches; s, gas- 

 tric folds; sm, muscles. 



seyiiliopolyp or scyphostoma, the sexual an acraspodote medusa. 

 In contrast to the Ilydrozoa the asexual stage pltiys a subordinate 



