PHYLUM CCELENTERATA 



133 



Order 3. Cubomedusae. -- SCYPHOZOA with four perraclkil 

 tentaculocysts; tentacles interradial; umbrella four-sided, cup- 



Gf 



FIG. 82. SCYPHOZOA. A, Tessera prince j>s, order STAUROMEDUS.E. B, Peri- 

 phylla hyacinthina, order PEROMEDUS.E. C, Charybdca marsupialis, order CUBO- 

 MEDUS.. G, gonads; Gf, gastral filaments; Ov, gonads; Rf, annular groove; 

 Rk, marginal bodies; Rm, circular muscle; T, tentacles. (From Sedgwick, 

 after Haeckel.) 



shaped; no alternation of generations. Example: Charybdea 

 (Fig. 82, C). 



Order 4. Discomedusae. -- SCYPHOZOA with four or more 

 perradial and four or more interradial tentaculocysts; umbrella 

 disc-shaped; alternation of generations. Examples: Aurelia 

 (Fig. 79), Pelagia, Cassia pea. 



4. CLASS III. ANTHOZOA (ACTTNOZOA) 



There are no medusae among the ANTHOZOA. The polyps 

 may be distinguished from those of the HYDROZOA by the pres- 

 ence of a well-developed stomodaeum or gullet, which is fastened 

 to the body-wall by a number of radially arranged membranes 

 called ^mesenteries. Many of the polyps are solitary, but the 

 majority produce colonies by budding. Most of the ANTHOZOA 



