36 I'EOE. A. DEISTDT ON THE 



papillae) extend from end to end of the body, being in approxi- 

 mately single series in tbe anterior and posterior portions, but 

 more numerous in tbe middle, especially on. the ventral surface, 

 where there are also a few scattered on the interambulacra. 

 Dissection revealed ampullae only on the ventral side, in the 

 middle part of the body. 



The entire body is covered with overlapping calcareous scales, 

 which give rise to the reticulate appearance of the skin observed 

 by Hutton. 



The anus is surrounded by a slight fringe of slender spicules. 

 The internal anatomy agrees very closely with that of Colo- 

 cMrus ocnoides, described below. There are two genital bundles, 

 right and left, attached to the dorsal mesentery a little in front 

 of the middle of the body. The Polian vesicle is single, dorsal, 

 much inflated, lying to the left of the single dorsal madreporie 

 canal. The respiratory trees are, as usual, attached to the 

 anterior end of a long rectum, and the alimentary canal resembles 

 that of C. ocnoides. 



The calcareous ring is composed of ten y-shaped pieces, with 

 their forks directed backwards (PI. 4. fig. 32). The radial pieces 

 are much longer and project much further backwards than the 

 interradials, so that the ends of the limbs of the interradiala 

 articulate with about tbe middle of the stems of the radials,' 

 which widen out somewhat at this point. The notch between 

 the two limbs of the radials is also much smaller than in the 

 interradials. 



The most abundant spicules are the large and small reticulate 

 plates or scales (PI. 4. figs. 21-24), measuring up to about 1 mm, in 

 diameter. In addition to these there are small, deep reticulate 

 cups (PI. 4. figs. 27-31), the margins of which are beset with a 

 variable number of very conspicuous, rather slender, short pro- 

 jections. These cups, with their crown-like margins, are highly 

 characteristic ; they measure about 0*02 mm. across the margin, 

 and about the same in depth. Perforated rods (figs. 25, 26) also 

 occur in boiled-out preparations. They doubtless belong to the 

 tube-feet. 



CoLOCHiEus OCNOIDES, n. sp. (PL 4. figs. 33-43.) 

 Body cucumiform, cylindrical, with the posterior third or 

 thereabouts strongly turned up dorsalwards and tapering to the 

 anus. Anterior end much more bluntly rounded (when the 



