90 SPOLIA ZEYLANICA. 



External Appearance. — The spirit specimen has a yellowish- 

 white ground colour. Numerous small brown spots are 

 scattered over the integument, but they are too small to 

 detect without the aid of a hand lens, except in the middle of 

 the trivium and irregularly on the bivium, where they are 

 much more crowded and produce brown markings. Most of 

 the papillse on the bivium are of a chocolate-brown colour, 

 thus standing well out upon the lighter background. I cannot 

 see the double circular ring around the papillae which Theel 

 described. The ambulacral appendages consist of papillae 

 only, which, as in Holofhuria spinifera, remain extended to a 

 considerable extent in the preserved specimen. The paj)illa) 

 are slightly smaller and more numerous on the trivium. The 

 largest papillae are found along each side of the body, as in 

 Holothuria spinifera. 



Internal Structure. — The calcareous ring is well formed and 

 the radial pieces are massive. I have found only one Polian 

 vesicle. Theel record^ seven from the " Challenger " specimen, 

 but this difference is not of importance. It is interesting to 

 note that the stone canal is very similar to that of H. spinifera, 

 both in its position and large size. Both branches of the 

 respiratory tree extend to the anterior end of the body, but 

 the left branch is the larger. Cuvierian organs are present. 



Spicules. — These consist of tables and knobbed buttons. 

 The discs of the table differ slightly from Theel's drawings, in 

 that they often have more holes and the edge of the disc 

 is more irregular. The disc has a diameter of 100 [>-, and 

 generally contains a large central hole surrounded by smaller 

 holes, but occasionally the disc is irregularly perforated and 

 contains numerous small holes instead of the single central 

 hole. The buttons are 65 [>- long and have three pairs of 

 holes. In the papillae there are a few tables of the usual type, 

 and a large number of massive rods perforated at each end, 

 and having a flattened perforated centre. 



General Distribution. — Indian Ocean. 



Remarks. — This species is undoubtedly related to H. 

 spinifera. The external differences are not very great, the 

 colouring of H. ocellata being generally more decided than 

 that of H. spinifera. The disposition of the papillae is the 



