ACTIXOPODOÜS HOLOTHURIOIDEA. 17 



riglit ventral interracliiis. A low median genital papilla, 1 cm. 

 behind tlio base of the tentacles, in a specimen 12 cm. long. 

 Respiratory 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 circulatory 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 w^all. 



RemarlxS : — The specimens described above agree in many 

 respects witli that described by Thkel under the name of 

 Stichopiis cliaUengeri. The main points of difference are : 



1) Dorsal papillae in Theel's specimen are described as 

 scattered over the ambulacra and interambulacra. An arrangement 

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

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

 ventral ambulacra ; whereas in my specimens the dorsal papillae 

 are in regular row^s as described above. But it must bo remem- 

 bered that Theel's specime]i was slightly macerated, and those 

 among my specimens which are not well preserved might easily 

 be described in Theel's woiyIs. 



2) The commonest form of the calcareous deposits in Theel's 

 specimen is quadriradiate, wliile in my specimens they are almost 

 without any exception of the triradiate cliaracter. There are only 

 a few four-armed exceptions in the walls of papillae and pedicels. 



My specimens are also very close to those described l)y 

 LrnwiG as Synallades alexandri. The only point of difference is 

 that raised as the second point of difference in the above com- 

 parison with Stichopus rhaUengeri All other differences are minor. 



Now w^e may regard the specimens of Th]:el and of Lt'dwig, 

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



