HOLOTHTJEIAIS'S OF NEW ZEALAND. 



39 



with a pink tip. Anus surrounded by five teeth, each overhung 

 <(in life) by a slender cylindrical process *. 



The largest specimen which I have seen measured, after pre- 

 servation in spirit, about half an inch long by rather less than 

 -j^ inch in greatest diameter. 



In spirit specimens the tube-feet and papillae appear to be 

 very irregularly arranged, and no distinct teeth are visible 

 around the mouth or anus. 



The integument is thick, friable and chalky white, owing to 

 the very numerous minute spicules which it contains. 



The pharynx is provided with a slender calcareous ring of ten 

 simple triradiate pieces, each with the odd ray pointing for- 

 wards (fig. 53). The radial pieces are rather larger than the 

 interradials, and differ from them in being deeply notched pos- 

 teriorly between the paired arms and in having the apex of the 

 odd arm slightly bifid. 



Eollowing on the pharynx the short slender oesophagus passes 

 ■directly into the wide intestine, the first part of which seems to 

 have thicker walls than the remainder, but does not appear to be 

 muscular. The intestine is rather wide throughout, looped in 

 descending, ascending, and descending portions as usual, but not 

 convoluted. The rectum is very short, the respiratory trees 

 springing from close to the anus. The respiratory trees are 

 short, digitate, with very short wide branches, very short even 

 in proportion to the size of the body. 



The reproductive organs consist of two small bunches of short 

 caeca, placed one on each side of the dorsal mesentery rather far 

 forward, just behind the oesophagus. 



E-etractor muscles as usual, but rather long and slender, spring- 

 ing from about the middle of the body. 



Madreporic canal single and dorsal. Polian vesicle single, 

 rather short, inflated, situated on the left side. 



The most abundant spicules are small, oval, reticulate plates 

 •or buttons, each with four perforations, and studded on both 

 surfaces ivith rounded, pearl-like knots, which give them a highly 

 characteristic appearance (PL 5. figs. 44-47). These spicules 

 measure about 0*062 mm. in longer diameter. There are typically 

 fourteen knobs on each side, arranged as shown in fig. 47, but often 



* I could not make certain whether or not similar processes occur also 

 between the teeth. The processes look like ambulacral appendages. 



