73 



very dark coloured form of tliis species I have seen in the British Museum, from 

 Tuticorin (Thurston ) ; the spines are greenish with brown rings. There does not seem 

 to be any other difference from the typical form, so that it can only be regarded 

 as a colour-variety. The Salm. sulcata named by Bell in his paper On Echino- 

 derms from the Neighbourhood of Zanzibar (loc. cit.) is identical with this form of 

 S. dussumieri. 



The alternation of the primary ambulacral tubercles has already appeared in 

 specimens of 6 — 7 mm. diameter; in younger specimens (and, of course, in the 

 proximal part of the ambulacra of larger specimens) there is a primary tubercle 

 on every ambulacral plate. The genital openings appear very early, being found 

 already in specimens of ca. 5 mm., a curious difference from S. sphœroides, where 

 they do not appear till the animal has reached a much larger size, c. 17 — 18 mm. 

 in diameter. 



The pedicellariæ are so very like those of S. sphœroides that scarcely a single 

 characteristic feature can be pointed out; reference may simply be made to the 

 figures given of the pedicellariæ of sphœroides. The spicules of the tube feet are 

 rather numerous and of the usual bihamate form. The buccal membrane, as in 

 the other species, contains a number of small, irregular plates inside the buccal 

 plates, forming a ring around the mouth; some few small, rounded plates may 

 occur outside the buccal plates but not especially opposite to the gills. Bihamate 

 spicules do not occur in great numbers in the buccal membrane; a few small, bow- 

 shaped spicules may be found among them. The walls of the intestine are full of 

 very small, bowshaped spicules. In the stone-canal the spicules are larger, elon- 

 gate, more or less irregularly branched. The genital organs are bushshaped, with 

 close, irregular branches. They are full of two kinds of spicules: the small, bow- 

 shaped ones, which, however, mostly develop to larger, branched spicules (mainly 

 in the stem), and very large, bihamate spicules (PI. VII. Fig. 15). 



A number of specimens of different sizes were taken at the following loca- 

 lities : Koh Kram, 30 fathoms, Koli Lan, 30 faths., between Koh Rin and Cliff Rock, 

 1Ô faths. (only small specimens), Koh Kam, 5 faths., Gulf of Rayong, 7—10 faths., 

 20 miles S. of Koh Samit, 20 faths., otf Tung Kaben, (5 faths., S. of Koh Kahdat, 

 8 — 10 faths. Also from Singapore I have specimens, taken by Mr. Gad, 1903. — 

 The species is found both on hard and on muddy bottom. 



A number of species of Salmacis have been described besides those men- 

 tioned above, viz: — 



Salmacis uarius Agass. (Catalogue raisonné des Echinides. p. 55.) 



— globator Agass. (Ibidem.) 



— rubrotinctus Grube. (45. Jahresber. Schles. Ges. vaterl. Cultur. 1868. p. 42.) 



— riifa Bell. (Echinoderms from Macclesfield Bank. Proc. Zool. Soc. 1894. 



p. 411. PI. XXVI. 2-3.) 



I) K I) Viilensk. Selsk SUr . 7 Ra^kke, naturvidensU og nwtlieni Aid 1 1. 10 



