56 



PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiii. 



spires are present on all of the outer plates as drawn by Duncan and 

 Sladen, 18S1 (Plate I, %. 6), but in older individuals I find that the 

 spires may occur only occasionally. This agrees with the important 

 and suggestive results obtained by Mitsukuri, 1897, for Stichojms 

 japonicus Selenka. 



Size of spire In mdllimeters.— Height 0.06 to 0.1, diameter 0.45. 



Crown generally bears from 6 to 40 teeth, average number 13 (fig. 6). 

 In some cases the teeth arise from projections which may be subdi- 



flG. 7.— CUCUMARIA CALCIGERA. PERFORATED PLATE OF THE INTROVERT. O, UPPER SURFACE; 



b, PROFILE. (X 166.) 



vided; in other cases the teeth are very small and difiicult to count, 

 or, again, they may be almost fused into one mass (tig. 5). 



Diameter of crown in millimeters. — 0.02 to 0.04, average 0.03. 



Perforated plates. — Smooth, round to four-rayed, holes arranged as 

 in the disk of the tables, or irregularly distributed. Sometimes 

 ridges arise running between the rows of holes. 



Size of plates in ririllimeters.—heugth 0.12 to 0.54, average 0.29; 

 width 0.09 to 0.45, average 0.15; thickness 0.008 to 0.03, average 0.02; 

 diameter of holes 0.008 to 0.03. 



Spicules of the introvert. — Irregular perforated plates with jagged 

 edges and bearing spines (fig. 7a); usually more numerous on one 



Fig. s.— Cucumaria talcigera. Supporting table from a pedicel, a, Upper Surface; 



6, profile, (x 340.) 



face than the other, as seen in the profile view (fig. 7^). The number 

 of holes varies from 1 to 21, average 5.4; the number of spines from 

 1 to 21, average 11.8, 



Size of plates in millimeters. — Length 0.11 to 0.27, average 0.17; 

 width, 0.08 to 0.11; average, 0.09. 



Spicules of pedicels. — No supporting rods other than the support- 

 ing tables (fig. 8a-J). 



