48 CCELENTERATA AND 



between the Strobila and adult is called the Ephyra. The 

 Ephyrae of Cyanea and Aurelia closely resemble each other ; 

 that of Cyanea is, however, a little larger than that of 

 Aurelia andhas a brown or reddish color. Both have aflat, 

 disk-shaped body, deeply emarginntedby sixteen incisions 

 of two depths ; in the more shallow of which the otocysts 

 are placed, while a single tentacle is found as a mere stump 

 in the deeper. The lips are very simple and without folds. 

 In vibrations of the umbrella the marginal lappets are 

 commonly raised above the aboral region of the bell and 

 then brought suddenly down below the mouth. 



A larval stage of Cyanea older than the Ephyra, which 

 approaches in many particulars the form of the adult, is well 

 marked on account of the great development of small fila- 

 ments placed at intervals over the aboral region of the bell. 



The larval stages of Gallinema and Dactylometra are 

 not known. 



Order V. Ctenophora. 



Free-swimming, gelatinous animals with spherical, 

 thimble-shaped or ovate forms. The external walls of the 

 body crossed by eight meridional rows of paddle-like flap- 

 pers. With or without tentacles. Single, large, compound 

 otocyst at one pole. Chymiferous tubes radially arranged. 

 Without proboscis. 



A. Ctenophora without tentacles (Nuda) . Beroe'. 



B. Ctenophora with tentacles (Tentaculata). 



I. Body spherical, without lateral lobes. Rows 



of flappers of same length. Pleurobrachia. 



II. Body with large lateral lobes. Rows of 



flappers unequal in length. Mnemiopsis. 



A. Nuda. 



Beroe (Miiller) . Body ovate, hat-shaped, with pinkish 

 color. No tentacles, no body lobes. Large central body 



