16 F. JEFFREY BELL. 



DESCRIPTION OF PLATES. 



ECHINODERMA. 

 PLATE I. 



Promacorhrinus Jcerguehnensis. 



FIG. 1. Disc and base of arms from the side to show the insertion of the cirri, and the form of the 



cirrus pit, and the shape of the disc, x 2. 

 FIG. 2. Disc and base of arms from below ; the central boss is more distinctly seen than in fig. 1. 



x n. 



FIG. 3. An arm from the side, x 3 ; the roughened edges of the joints are well seen in this figure ; the 

 proximal pinnules only are completely shown. 



PLATE II. 



Antedon adriani. 

 General view of this Crinoid. x 2. 



PLATE III. 



Heuresasfer hodgsoni. 



X not quite f, seen from below, to show the breadth of the ambulacra! grooves, their size and 

 arrangement. 



PLATE IV. 



The young Ophiurid (see p. 14). 

 FIG. 1. Aboral view of disc and arm. x f. 

 FIG. 2. Oral view of same. X f . 



FIG. 3. View of mouth to show arrangement of the oral and adjacent plates, x 8. 

 FIG. 4. 1st, 2nd, and 3rd upper arm-plates, x 10. 

 FIG. 5. View of arm from above, at about its middle, x 10. 

 FIG. 6. 1st, 2nd, and 3rd lower arm-plates, x 10. 

 FIG. 7. View of arm from below at about its middle, x 10. 



PLATE V. 



FIG. la. Variety of Cycethra (see p. 10) from above ; fig. Ib from below ; both slightly reduced. 



FIG. 2a. Disc of an Ophiosteira (see p. 12), magnified to show keel-like plates ; 2a, seen from above ; 



2b, seen from the side. 

 FIG. 3. Pseudopsolus f&rrari. x ?,. 



