HOLOTHUBIANS OF ITEW ZEALAND. 33 



they are prolonged backwards each into a pair of long slender 

 many-jointed processes, the hinder extremities of which curl 

 inwards at the bottom of the pharynx. These bifurcate prolon- 

 gations are about an inch in length. The interradials are of 

 about the same width as the radials in front, and are continued 

 backwards between the bifurcate processes of the latter, for 

 about three quarters of an inch, each in the form of a long flat 

 rod made up of many joints. Owing to their much greater 

 width, the backward prolongations of the interradials are much 

 more conspicuous than those of the radials. 



The entire ring closely resembles that of Gucumaria conjungens, 

 as figured by Semper*; but in our species the interradials are 

 prolonged much farther backtvards, and the radials and inter- 

 radials are separated by considerable intervals, instead of touch- 

 ing one another as in Semper's figure. This last feature is, 

 however, probably dependent upon whether or not the pharynx 

 is distended by the enclosed tentacles, as it is in our specimen. 



There is a single dorsal madreporic canal running forwards for 

 a short distance along the pharynx by the side of the genital 

 duct. There are two Polian vesicles, situate ventrally, and 

 remarkable for their great length and slenderness (fig. 19). 

 Each is rather more than two inches long, so that when pulled 

 out they reach backwards from their attachment at the hinder 

 end of the pharynx to beyond the hinder end of the body. 



Following immediately on the pharynx, the alimentary canal is 

 for a short distance thick-walled and tubular. The thin-walled 

 narrow intestine is very long indeed, and very greatly convo- 

 luted, the posterior portion, for some distance before the rectum, 

 being twisted into a close spiral. The rectum is about an inch 

 long, and attached to the body-wall by numerous radial muscles. 

 The respiratory trees are strongly developed, copiously branched, 

 with four main branches, one branch lying in each interam- 

 bulacrum except the mid-dorsal. 



The single specimen is a female ; and the ovaries consist of two 

 remarkably small bunches of short, slender tubes, attached right 

 and left to the dorsal mesentery a little in front of the middle 

 of the body. The single oviduct runs up along the dorsal 

 mesentery as usual. 



The spicules are flat reticulate scales or plates (PI. 3. fig. 20), of 



* ' Eeisen im Arcliipel der Philippinen— Holothurien,' pi. xiv. fig. 4. 

 TilNN. JOUBN. — ZOOLOGY, VOL. XXVI. 3 



