134 THE ANATOMY OF IXVERTEBRATED ANIMALS. 



C^-^ 



A 



Fro. 28.— I and II —( )/n„(r<i cainJIafa (after Van Benedeni). 



I. Two Hi/iint t'lbie (iScyph/t-toma sta<?e), exhibitinij their ordinary character?, and 



between them two (a, h) wliich are undergoing fission {Strobila f^ta^e). 



II. The two StrobilCB, a and b. three day^s later. In «, tentacles are developed be- 

 neath the lowest of the Ephijrce, from the stalk of the Strobila, which will persist 

 as a Hydra tuba. 



III. Tlalr the disk of an Ephyra of Aurelia avrita, seen from the oral face. The 

 small tentacles which lie between the month and the band of circular muscular 

 fibres are inside the somatic cavity, whence sixteen short and wide radial canals 

 extend to the periphery, where they are united by transverse branches. Eight 

 of the radial canals enter the corresponding lobes, and finally divide into three 

 branches: one which enters the peduncle of the lithocyst. and two lateral caeca. 

 Radiating bands of muscular fibres accompany those canals. 



IV. Side view of one of the lithocvsts with its peduncle. The arrow indicates the 

 direction in which the cilia of (he exterior work. 



^ " Recherclies sur la Faunc littorale de Belgique. Polypes." 1866. 



