ACTIN'OrODOX'S IIOLOTHUPJOIDEA. 1 7 



ri,<,'lit veiifral iiitci'nidius. A low modian genital ]ia}iillii, 1 cm. 

 bohiiiil tlu' Ijasc of tlio Icntaclos, in a spt'cimou 12 cm. long. 

 Eespiratoiy trees two, their branches not long. The common part 

 rather long, being 2.5 cm. long in a specimen of 1 2 cm. length. No 

 relation with the cii'culatory system. Tentacular ampullae repre- 

 sented by slight elevations. Calcareous ring constituted as shown 

 in textfig. 2 a. No calcareous deposits in genital organs, respiratory 

 trees or cloacal wall. 



Ecmarhs : — The specimens described above agree in many 

 respects with that described by Theel under the name of 

 Stichopus challengeri. The main points of difference are : 



1) Dorsal pa])illae in Tukel's specimen are described as 

 scattered over the ambula.cra and interambulacra. An arrangement 

 of them in rows is scarcely to be found elsewhere than along the 

 sides of the liody, wjierc they evidently belong to the lateral 

 Ncntral ambulacra ; wliereas in my specimens the dorsal pajtillae 

 are in regular rows as described above. But it must be remem- 

 bered that Thkel's sjK'cimen was slightly macerated, and those 

 among my specimens which are not well preserved might easily 

 be described in Tukel's w(^rds. 



2) The commonest f(M'm of the calcareous deposits in Thkel's 

 specimen is quadriradiate, while in my specimens they are almost 

 without any exception of the fi'ii'adiate character. Tliere are only 

 a few fotu'-armed exceptions in tlie walls of paj)illae and j^edicels. 



My specimens are also very (!lose to those described by 

 LuDwrr; as Synallactes alexandii. The only point of diffcn'ence is 

 that I'aised as the second ]ioint of difference in tlie above com- 

 parison with Slichoptis challengeri. All other differences are minor. 



Now we may regard tlie specimens of Thkel and of Lvdwig, 

 as well as my mvn, as all belonging to one species, in which case my 



