234 CQ'LEXTKRATA 



organs, and wliicli must he regarded as Iransxerse rows of long agglutinated 

 cilia. The I'onihs (Ug. J07A) arise from thick epilltelial ridges, lrans\'erse 

 to the meridional bands, and are so far apart that the free edges of one 

 comb overlap tiie base of the next like shingles. In consei(iience of their 

 hlirotts striicltire the combs are strongh' iridescenl and in molioit cause a 

 beautifid pla}- of metallic red, blue, and green o\"er the meritlional bands 

 These combs act like oars and row the body about. Since tire comlis 

 begin some distance from the aboral pole, thev are connecteil with it by 

 means of ciliated groo\es following the line of the meridional bands. 

 Experiment shows that the sense liod\' is an organ of equilibration and for 

 correlating the action of the different rows of combs. 



The ectoderm gives origin to two other important organs, two pole fields 

 and two tentacles. The piole fields (tig. 20Q, pp) are two epithelial patches 

 extending a short distance in tlie sagittal axis from the sense boily and 

 possibly are olfactory or taste organs. The tentacles arise, in the trans- 

 verse axis, from the bottom of deep tentacular sacs (tig. 207, /'-) 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 adhesi\e cells. These are 

 spherical bodies (tig. 210) covered with a very sticky granular secretion, 

 and, like a VorticcUa, supported on tlie end of a spiral 

 stalk muscle. These are used in capturing prey, w hich 

 adheres to them and is drawn inward by the muscles. 



The ectoderm also forms part of the gastrovascular 



system. It turns inward at the mouth — situated at 



the lower end of the chief axis — and lines tire large 



space commonlv called stomach (fig. 207, ;»), biit which 



corresponds to tJre crsophagus of the Actinozoa. At 



the aboral end of this stomach begin the true cnto- 



dermal portions, the so-called fiiinuh, and from them 



y,f; 210— A.I- ''"'^ canals distributed through the jelly to the ^-arious 



hesi\e cells ef organs. 'Ywo (rarelv four) funnel canals run to the 



Clenoiihora lafkT 1111 ,- ^ , , , 



Samassa). al.iorai pole and emjit)- (lig. 20c), /<>) near the sense body; 



a second jiair, the parai^cixlrif raiuils (lig. 207, Dig), 

 which run parallel to the a'sophagus, end blindly. The perradial canals 

 (g) proceed outward from the funnel, and besides gi\'ing off a canal to the 

 base of the tentacle, each di\ides dichotomouslv twice, lirsl into interradial 

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

 nal vessel running just beneath a row of combs, nourishing them as well 

 as the gonads. The gon:',ds consist of two bands, one male, the other 

 female, running in that wall of the meridional vessel nearest to the combs 



