38 CCELENTEEATA. 



Order II. T^ENIAT^E. 



Body ribbon-shaped, without oral lobes. Tentacles two, near 

 the mouth. 



Each half of the ctenophoral system is represented by four 

 very long canals. 



The common Mediterranean species, known as " Yenus's girdle " 

 (Cestum veneris), has a flat, ribbon-shaped body, three or four 

 feet in length, and a height of about two inches. 



Cestida. 

 Cestum. 



Order III. SACCATE. 



Body oval or spheroidal, without oral lobes. Tentacles two, 

 away from the mouth. 



The filiform tentacles are fringed in Cydippe on one side, and 

 can be withdrawn instantly into the sac of the lateral actinomeres, 

 at the will of the animal. 



This and the two preceding orders are united by Von Hayek 

 under the name of Stenosomata. 



Cydippidce. Gegenbauria. 



Cydippe = Pleurobrachia. Owenia. 



Eschscholtzia. 



Callianirida. 



Mertensiida. Callianira. 



Mertensia. 



OrderlV. EURYSTOMATA. 



Body oval or oblong, without oral lobes. No tentacles. Mouth 

 very large. 



The mouth and digestive cavity are large, unlike the remainder 

 of the class. Beroe itself is of the size and shape of a lemon. 



Beroidce. Neisides. 



Berog. Neis. 



Idyia. 



Pandora. Rangiidce. 



Rangia. 



