264 C(EL ENTERA TA. 



bottom of deep tentacular sacs, from which they project as long 

 cords with numerous lateral branches, and into which they may be 

 retracted. Tentacles and branches contain an axial muscle, while 

 the ectodermal coating consists largely of adhesive cells. These 

 are spherical bodies (fig. 224) covered with a very sticky granular 

 secretion, and, like a Vorticella, supported on the 

 end of a spiral stalk muscle. These are used in 

 capturing prey. 



The ectoderm also forms part of the gastrovascu- 

 lar system. It turns inward at the mouth situated 

 at the lower end of the chief axis and lines the 

 large space commonly called stomach (fig. 221, 

 m) but which corresponds to the oesophagus of the 

 Actinozoa. At the aboral end of this stomach 

 begin the true entodermal portions, the so-called 

 FIG 224 Adhesive f unne l s > an( l from them the canals distributed 

 phora f (Aner through ^ ne j 6 ^ t * ne various organs. Two 

 Samassa.) (rarely four) funnel canals run to the aboral pole 



and empty (fig. 223, to) near the sense body; a second pair, the 

 paragastric canals (fig. 221 B, mg), which run parallel to the 

 03sophagus, end blindly. The perradial canals (c.pr) proceed out- 

 ward from the funnel, and besides giving off a canal to the tentacle 

 (tg) each divides dichotomously twice, first into interradial and 

 then into adradial canals, each of these last connecting with a 

 meridional vessel running just beneath a row of combs, nourishing 

 them as well as the gonads. The gonads consist of two bands, one 

 male, the other female, running in that wall of the meridional ves- 

 sel nearest to the combs. In spite of their position they are 

 apparently ectodermal in origin. 



These gonads are regular in distribution, those of two vessels 

 which are nearest each other being of the same sex. The eggs and 

 sperm pass out through the gastrovascular system. 



The few species of the group are divided into the TENTACULATA, 

 with tentacles, and the NUDA, without. To the first belong the CYDIP- 

 PID^E, with pear-shaped bodies (Pleurobrachia* on our coast, fig. 222), and 

 Hormiphora (fig. 221); the LOBAT^E (Mnemiopsis,* Bolina*), with lobes; 

 and the band-like CESTID^E (Cesium, the Venus girdle) of the warmer 

 seas. The BEROID.E (Beroe, Idyia*}, with wide mouth, belong to the 

 Nuda. The small creeping forms, Cceloplana and Ctenoplana, are supposed 

 by some to form a transition to the Turbellaria. 



