VIII 



ECHINODERMA TA PEDICELLARIA^ 



395 



pedicellate are further attached by a strong elastic fibrous band to 

 this"same plate. 



li. Stalked pedieellarise (Fig. 342, H, K). Each pedicellaria 

 rises from a short, soft stalk ; the blades, of which there may be two 



R B 



K 



FIG. 342. Pedicellariae of Asteroids. A, B, C, D, E, F, Pseudo- or commencing pedicellarkc of 

 various species. G, Sessile pedicellaria from the edge of the ambulacral furrow of Gymnctiti'fiti 

 en i- in ifera (after Cue'not). H, Stalked straight pedicellaria diagrammatised (after Cuenot). J, 

 Basal portion of a stalked crossed pedicellaria of Afti'fCMtnthwn rnbcns (after Perrier). K, A 

 similar pedicellaria of Asteracanthion glacialis (after Cuenot). 1, Calcareous blade of the forceps ; 

 2, basal piece ; 3, occlusor muscle ; 3i, axial muscles of the blades ; 4, opening muscle ; 5, axial 

 band ; 0, epithelium ; 7, body wall ; 8, stem. 



or three, articulate with a basal skeletal piece. The double-blade* 1 

 (didaetyle) pedicellarise are either straight (forfteiform) or crossed 

 (foreipiform). Both kinds may be found in one and the same 

 animal. 



We select for description Asterias (glacialis), one of the Asteroid* 

 most richly provided with pedicellarise, whose arrangement is specially 

 interesting. 



A. glacialis has three kinds of pedicellarise, straight, crossed, and 

 three-bladed. 



The crossed pedicellarise are found in very great numbers, thickly crowded 

 together on a soft cushion, which surrounds the base of the spines, and into which the 

 latter can be withdrawn (Fig. 344). 



