66 SPOLIA ZEYLATSriCA. 



Holoihuria cinerasce.ns, Lampert 1885 (19) ; Ludwig 1887 



(28), 1897 (32) ; Sluiter 1901 (41) ; Bedford 1902 (3). 

 Holothuria wilkyi, Bedford 1902 (3). 



Several sjDecimens from the Maldives (Gardiner), Seychelles 

 (Dublin Museum), and Ceylon (various localities). 



External Appearance. — Reddish-brown colour, lighter below 

 and "with some irregular dark patches above. The trivium is 

 clearly separated from the bivium by reason of the disposition 

 of the ambulacral appendages. Those on the trivium are 

 pedicels which are closely arranged. There is sometimes a 

 very narrow bare area in the mid-ventral line which separates 

 the pedicles into two groups. The papillae on the bivium are 

 few in number and smaller in size than the pedicels, and are 

 irregularly scattered. There are twenty large yellow tentacles. 



Internal Structure.— The calcareous ring is large, the radial 

 pieces being very well formed. In the specimens I have 

 dissected there are two large Polian vesicles, one on the 

 central radius of the trivium and one on the left radius of the 

 bivium. There is a single stone canal on the right side of the 

 dorsal mesentery. In this species both the Polian vesicles 

 and stone canals vary in number to a considerable degree. 

 The right respiratory tree extends to the anterior end of the 

 body, but is very delicate. The left respiratory tree is much 

 shorter, but more massive. Cuvierian organs are not present 

 in the specimen examined by me, but they have been recorded 

 in this species. 



Spicules. — The deposits consist of small tables and spiny 

 rods. The tables are intermediate between those of H. atra 

 and H. edulis, but smaller. Sometimes the disc consists of a 

 simple ring as in H. edulis, but in the more perfect condition 

 it is more like that of H. atra. The diameter of the disc is 

 36 [L. The height of the table is about 40 [j., and it has a 

 spiny top similar to that seen in H. atra. The spiny rods are 

 similar to those of H. lubrica. They are slightly curved and 

 are covered with very minute spines, which are larger at the 

 two extremities. The rods are about 100 jji, in length and 

 16 ^. in width. 



General Distribution. — Indo-Pacific region. 



