HOLOTHURIOIDEA OF THE mDIAN OCEAN. 83 



Spicules. — The deposits consist of tables and buttons. The 

 tables consist of a disc 90 H- in diameter consisting of a 

 central hole and a dozen or more peripheral holes. In the 

 most complete form the tables bear long spines on the edge of 

 the disc. There is a well-developed tower having a height of 

 65 [X, and consisting generally of four uprights which converge 

 towards the summit of the tower, and which are joined 

 together by a cross-piece. These supports bear spines about 

 liaH-way up. The top of the tower bears a number of long 

 spines, some of them 50 t^ in length, which radiate outwards 

 from the centre. Many of the tables show signs of disintegra- 

 tion. Frequently the spines on the outside of the disc and 

 on the top of the tower are either absent or very much reduced, 

 and sometimes the disc is so much reduced that instead of a 

 circle of holes there is merely a serrated border. 



In the Maldives specimen the buttons are extremely scarce, 

 and are apparently only present in and about the pedicels 

 and papillae, but in a specimen from the Indian Museum the 

 buttons are evenly scattered. It is possible that the buttons, 

 which are extremely delicate, have been dissolved out of the 

 Maldives specimen through the action of formalin, since most 

 of the tables are much reduced. The buttons are irregular, 

 and generally have four or more pairs of holes, but the buttons 

 are frequently asymmetrical in regard to the number of 

 holes. 



Remarks. — 8o far as I can judge from the descriptions it 

 would appear that H. triremis, Sluiter (46), is identical with 

 Ludwig's species, although there are some differences in the 

 two accounts. The Maldives specimen appears to link up 

 Ludwig's and Sluiter's specimens. Ludwig's single specimen 

 was light yelloAv, and had twenty yellow tentacles. The 

 body was marked by five radial ridges and by several transverse 

 wrinkles, probably due to ante-mortem contractions. The 

 trivium bore numerous pedicels and the bivium less numerous 

 papillae. Sluiter's specimens were reddish-brown colour and 

 had twenty brownish-voilet tentacles. The pedicels were 

 arranged in three distinct double rows on the trivium, and the 

 numerous papillae stood on conical warts and were irregularly 

 arranged. It is with regard to the spicules that the two 



