158 



PHYLUM CCELENTERA. 



closely allied to Aurelia some, e.g. Pelagia, have a direct development 

 without the intervention of Scyphistoma or Strobila stages, but this 

 may occur exceptionally in Aurelia, Cyanea is often very large, 



FIG. 76. Lucernaria. After Korotneff. 



"it may measure 7| ft. across the bell, with tentacles 120 ft. long." 

 Chrysaora is hermaphrodite, and has diffuse sperm sacs even upon 

 the arms. In the Rhizostomae, e.g. Cassiopeia and Pilema, the 



FIG. 77' Diagram of Lucernaria. 

 After Allman. 



C. t Cavity of gut (coelenteron) ; F. t gastric fila- 

 ments; //., hypostome ; G., gonad ; T., tentacle ; 

 c.c., circumference canal. 



mouth is obliterated, and replaced by numerous small pores on the 

 four double arms. Lucernaria and its allies are interesting sessile 

 forms which have been compared to sexual Scyphistomas, that is, are 

 regarded as persistently larval forms. 



