46 PEOr. A DENDT ON THE 



Oa referring to the Dunedin specimen of " T. caudatum,'^ how- 

 ever, I found the calcareous ring (fig. 66) to be practically 

 identical in structure with that figured by Theel for " T. 

 rugosufn^ and also witli that of the type specimen of T. longi- 

 dentis (compare figs. 62 and 66). Now neither the actual 

 specimens nor the figure referred to show what I should term 

 " five slender bifurcate prolongations " or " bifid teeth. ; " and I 

 am inclined to think that there has been a good deal of confusion 

 in the terminology and description of the parts of this very 

 complex structure. Again, in describing T. lonqidentis, Hutton 

 says — " The dental aparatus is composed of five plates, each 

 bifid for half its length, joined to one another, and the lateral 

 process of the two adjacent plates together form a tooth." As 

 a matter of fact each interradial plate bifurcates posteriorly and 

 the divisions unite in pairs to form the five slender radial pro- 

 longations or teeth, exactly as shown in Th eel's figure for 

 " T. rugosumr 



I found in the Dunedin specimen a single madreporic canal and 

 a single much elongated Polian vesicle placed nearly opposite to it. 

 The spicules (PL 6. figs. 67-69) are like those figured by Theel 

 for " T. rugosum ;" but both in the Dunedin specimen and in 

 Hutton's type-slide of " T. caudata " there are plenty of irre- 

 gularly quadriradiate ones like those of the type of T. longidentis. 



Comparison of Theel's figures of the spicules and calcareous 

 ring of " T. rugosum " and my figs. 62-69, representing the corre- 

 sponding parts in " T. caudata " and T. longidentis, will, I think, 

 leave little doubt in the mind of the reader that the three are 

 specifically identical. 



Stichoptjs mollis, Sutton, sp. (PI. 7. figs. 73-82.) 



1872. Holothuria mollis, Hutton, Cat. Echinoderm. N. Z. p. 15. 



1879. Holothuria mollis, Hutton, Trans. N. Z. Inst. vol. xi. p. 308. 



1886. Holothuria mollis, Theel, ' Challenger' Holotkurioidea, p. 239. 



1886. Stichopus sordidus, Theel, ' Challenger' Holotkurioidea, p. 167, 

 pi. viii. fig. 3. 



The original description runs as follows : — " Body soft, taper- 

 ing slightly posteriorly ; a row of large tubercles like suckers 

 on each side, and another row of fewer suckers on each 

 side of the back; lower surface with many small suckers 

 irregularly placed ; tentacles twenty, shortly peduncled, on 

 hollow cylinders, and ending in frondose appendages, which are- 



