482 



GOMPABATIVE ANATOMY 



g«-- 



FiG. 384.— Radialinterradial section in the direction of the principal axis through the 

 calyx of Pentacrinus decorus (after P. H. Carpenter), left half radial, riglit iuterradial, dia- 

 "■rammatic. In many respects the figure is obsolete and incorrect. The most noteworthy points 

 are emphasi.sed by special type in the following lettering, sa, Subambulacral plates ; rii, radial 

 nerve trunk (hatched) ; rv, radial pseudohwmal canal (black) ; ra, radial canal of the water vasculai- 

 system (dotted); d\, brachial crelom ; pi, spongy organ of the blood vascular system; ac, circular 

 canal of the water vascular system ; o, mouth ; <in (to the right), nerve ring ; av, blood vascular 

 ring? pseudoliiemal ring'.'; an (to the left), anus; re. rectum ; in, plates of the interambulacral 

 areas ; pa, calyx pores ; (7, the coelom, traversed by a spongy network ; it, intestinal coils 



(cut through); ;/;i, axial organ; /«/(, muscles ; ''(., www ciinniiissurc between tlie axial trunks; 



h(i, l>asal ; cr, cinns canal ; en, cirrus nerve ; cli, chambered sinus, with the centre of the apical 

 nervous system; r, radial plate; ci, c-.., first and second costal; (//, distichal ; n//, syzygial 

 suture ; ;/;■, genital canal ; am, apical nerve trunk of the arm. 



