70 SPOLIA ZEYLANICA. 



varying degrees of black pigment. The black is very well 

 marked on the bivium, where it varies from a grayish colour 

 to an intense black, which at each side is gradually replaced 

 by pink. The trivium is nearly always devoid of black. 

 When preserved in sj)irit this species loses its pink colour and 

 generally appears black above and gray below . There are pedi- 

 cels on the trivium and papillae on the bivium. The tube feet 

 are readily distinguished, as each one is generallj" surrounded 

 by a narrow black ring and has a white sucking disc. An 

 arrangement into three rows is sometimes discernible. The 

 papillae are small and not very numerous. They are generally 

 of the same colour as the general integument, so that they 

 are not easily seen. There are twenty pinkish-white tentacles 

 surrounded by a rim of small black papillae. The anus is 

 round and the diaphragm is black. 



The hving animal is long and narrow and may measure up 

 to 400 mm. in length and 50 mm. in width. Spirit specimens 

 are much shorter than this. 



Internal Structure. — Internally this species differs but httle 

 from Holothuria atra. In both species the calcareous ring is 

 similar, the Polian vesicles and stone canals are numerous and 

 variable, and there are no Cuvierian organs present. The 

 number of Polian vesicles varies from one to three, and the 

 stone canals vary in number from 20 to 40, being disposed on 

 each side of the dorsal mesentery. The circum-cesophageal 

 ring is about 20 mm. behind the calcareous ring. Both right 

 and left branches of the respiratory tree are large and of 

 equal size. 



Spicules. — These are similar to those of Holothuria atra, 

 except that the disc of the tables is represented only by 

 a ring. 



Distribution. — Littoral waters of the Indo-Pacific region. 



Remarks. — ^This species is undoubtedly related to Holothuria 

 atra, but differs from the latter in the colour of the body and 

 in the nature of the calcareous tables. I have had the 

 opportunity of examining large numbers of this species on the 

 Ceylon Pearl Banks, and have always found the pink colour 

 to predominate over the black. At Trincomalee and Jaffna, 



