92 SPOLIA ZEYLANICA. 



I am inclined to believe that the specimens are young 

 forms of H. ocellata, and the differences in the spicules are 

 probably due to the fact that as the animal grows older the 

 spicules become smaller owing to disintegration. This has 

 been observed in other species by Mitsukuri and the present 

 writer. 



HoLOTHUEiA MARTENSii, Semper. 



(Plate XIV., fig. 25.) 



Holothuria martensii, Semper 1868 (38) ; Ludwig 1882 (26) ; 

 Lampert 1885 (19) ; Theel 1886 (42) ; Pearson 1910 

 (34). 



A few specimens from the Australian and American 

 Museums. 



External Characters. — The preserved specimens I have been 

 able to examine have exactly the same appearance as Holo- 

 thuria spinifera, but as I have only examined Uving specimens 

 of the latter and not of the former, I cannot say whether the 

 resemblance is as close during life. The colour of a specimen 

 preserved in spirit is a uniform yello-wdsh-white both above 

 and below. The body is covered with papillae, which are 

 larger along each side of the body than elsewhere. 



Internal Structure. — Internally the resemblance with Holo- 

 thuria spinifera is maintained. The calcareous ring is similar 

 in shape and size. There is a single long PoUan vesicle and a 

 very large stone canal similar to that already described in 

 H. spinifera and H. ocellata, the only difference being that the 

 free end is pear-shaped as in the specimen described by Theel. 

 Both Semper and Lampert have described the presence of 

 two Polian vesicles and one extremely small stone canal. In 

 specimens examined by me the stone canal is large in every 

 case, and there is only one Polian vesicle. On these points I 

 am in agreement with Theel. It would seem as though Semper 

 and Lampert had mistaken the stone canal for a Polian 

 vesicle, to which it offers a distinct resemblance. Such being 

 the case it is difficult to know what structure they have 

 interpreted as " der Steinkanal ausserst klein." The right 



