ir. crENoriiORA. 203 



maSvS of otoliths, supported on four bundles of S-shaped agglutinate 

 cilia. From these bundles of cilia eight bands of thickened epi- 

 thelium, at first in pairs (fig. 223, ivs), later diverging, pass to the 

 oral pole (fig. 221, r). These meridional bands (so called from 

 their course) consist in part of ciliated epithelium, in part of the 

 characteristic ' combs ' which are the locomotor organs, and which 

 must be regarded as transverse rows of long agglutinated cilia. 

 The combs (fig. 219) arise from thick epithelial ridges, transverse 

 to the meridional bands, and are so far ajsart that the free edges 



Vui. -it 



Fis. 223. 



Fli 



ira. ,-), throut,'}! th<' rrMitrr- : T^". oxceiitrif ; 

 i.)f otoliths, (( ; p, pi^ciiiuiit ci'll ; .-;'-, si'iisui-y 



— StM-tioTi of SL-nsi.' body t)f Cn/huii 

 fl, roof of seiiborv groove ; /, support 

 ccUs. 



Fig. tsn.— Aboral polo of CidlUinirn hinUita. fpTum I.aiik'J ./. siijiports of otolillis, 

 " ,' PP^ polo phite : 5/.', sense body; /o", opeiiiiii^s of g;istra! t'unuf'ls; ^r.v, cilialed 

 bands- 



of one comb overlap tlio base of tlie next like sliiiigles. In conse- 

 quence of tlieir fibrous structure tlie coniljs are strongly iridescent 

 and in motion cause a bea-utiful play of metulli(- reil, blue, and green 

 over the meridional liands. Tlicse coiuIjs act like oars and mw 

 the body about. Since the comljs begin some distance from the 

 al)oral pole, they are connected with it l)y means of ciliated grooves 

 following the line of the moidional hands. Exjieriment slifjws 

 tliat the sense body is an organ of equililjration and of correlating 

 the action of the different rows of combs. 



The ectoderm gives origin to two nioj'e important (irgan.s, two 

 pole fields and two tentacles. The pole fields (fig. 221, /»; 22-'l. j)/!) 

 are two epitlielial i)atches extending a sliort distance in tlie 

 sagittal axis from the sense body and possilily are olfactoiy or 

 taste oro-ans. The tentacles arise, in the transverse axis, from the 



