264 CCELENTEBATA. 



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

 cords with numerous lateral ?jranclies, 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 Voriicella, supported on the 

 end of a spiral stalk muscle. These are used in 

 caj^turing 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. 231, 

 ?n) 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 ^^^iiels, and from tliem the canals distributed 

 cells of cteno- through the ielly to the various orarans. Two 



phora. (After ^ .) J to 



samassa.) (rarely four) funnel canals run to the aboral piole 



and empity (fig. 223, to) near the sense body; a second jjair, the 

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

 ceso|)hagus, end blindly. The perradial canals (c.pr) proceed out- 

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

 (/£/) each divides dichotomously twice, first into interradial and 

 then into ad radial 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 

 ajjparently ectodermal in origin. 



These gonads are regular in distribution, those of two vessels 

 which are nearest each otlu^' 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, aud the NUDA, without. To the first Ijeloug the Oydip- 

 PiD/K, with pear-shaped bodies (Pleuivbrachhr^ on our coast, tig. 22'2), and 

 Jfornuphora (fig. 221); tlie Lobatje (iViiemiopsis* Bol/iia'^), with lohes ; 

 and the band-Hlce Cestid.h (Ccstinii, the Venus girdle) of tlie warmer 

 seas. The Beiioidjo (Beroe, I</i/>ir'-), with wide mouth, belong to the 

 Nu(hi. The small creei>iug forms, Cwloplaiia and Cteiwphiiia, are supposed 

 l>y some to form a transition to tlie Turbellaria. 



