Holothurians.] SUBANTARCTIC ISLANDS OF NEW ZEALAND. 153 



As to C. dunedinensis, this species is not rare, as Lyman Clark surmises.* In 

 company with Professor Benham, I collected it in quantity myself at Dunedin in 

 July, 1898, and have still numerous specimens in my possession, but those which I 

 have examined do not show any dark spots on the inner side of the tentacles, as 

 described by Parker, f 



The apodous Holothurians have recently been the subject of a revised classifi- 

 cation by Dr. Lyman ClarkJ, who recognises no less than seven genera in the sub- 

 family Chirodotinae, distinguished from one another largely by the presence or 

 absence of wheels and sigmata (hooks) and by the arrangement of the wheels, 

 whether scattered or in papillae. 



The genus Rhabdomolgiis is placed by Clark in the subfamily Synaptinae ; if 

 we include it, as I prefer to do, in the Chirodotinae, we see that five species of this 

 subfamily have been found in the New Zealand area, viz. : — 



(1.) C. dunedinensis, Parker, with 10 tentacles, numerous comparatively large 

 scattered wheels and sigmata. 



(2.) C. henhami, Dendy, with 10 tentacles, very few small scattered wheels and 

 numerous sigmata. 



(3.) C. geminifera, Dendy and Hindle, with 10 tentacles, numerous rather small 

 sigmata, but no wheels. 



(4.) C. gigas, Dendy and Hindle, with 12 tentacles, with wheels partly collected 

 in papillae and partly scattered, and with curved rods in place of sigmata. 



(5.) Rfiabdomolgus novae-zecdandiae, Dendy and Hindle, with ten tentacles and 

 no spicules at all. 



The first three of these species are evidently all closely related to one another ; 

 so much so that I have even doubted whether they ought to be considered as more 

 than varieties of one and the same species. The general anatomy and the form 

 of the sigmata and wheels (when present) clearly indicate their affinity. 



C. gigas is obviously a very distinct species, and is very instructive with regard 

 to the value to be attached to the arrangement of the wheels in papillae. 



The relationships of Rhtbdomolgus novae-zealandiae are less obvious, but it 

 appears to be derived from a Chirodota similar to C. dunedinensis by complete loss 

 of spicules. 



The study of these New Zealand species makes it perfectly clear to my mind 

 that the presence or absence of wheels and sigmata, and the arrangement of the 

 wheels (in papillae or scattered), cannot reasonably be used as the main basis for a 

 generic classification of the subfamily, and until some more satisfactory proposal 

 is forthcoming I prefer to revert to the old generic name Chirodota for, at any rate, 

 the New Zealand species of the subfamily, with the exception, for the present at 

 least, of Rhahdomolgus novae-zealandiae. 



* " The Apodous Holothurians," " Smithsonian Contributions to Knowledge," vol. xxxv, 1907, 

 p. 124. 



t " On a New Holothurian (Chirodota dunedinensis, n. sp.)," Trans, and Proc. N.Z. Inst., vol. xiii, 

 p. 418, 1881. 



{ Op. cU. 



