HOLOTHURIOIDEA OF THE INDIAN OCEAN. 69 



ends, and the edges of tables are not ixsually spinous. Theel, 

 however, has pointed out that H. atra sometimes has a spiny 

 disc, and Bedford has showii that amboinensis may have no 

 spines on the disc. The colour differences are apparently not 

 constant, so that the distinctions between the two forms do 

 not appear to be well defined. 



H. pulla, Selenka, resembles H. atra in general appearance 

 and in deposits, calcareous ring, and in the large nvtmber of the 

 stone canals. But it has Cuvierian organs according to 

 Theel, and it is this character alone which separates it from 

 H. atra. 



Distribution. — A shallow-water species, generally found 

 within the 10-fathoms hne and often between tide-marks. 

 Principally Indo-Pacific, where it appears to be universally 

 distributed between latitude 25° N. and 25^ S. Also found in 

 few places in West Indian area of Atlantic. 



HoLOTHURiA EDULis, Lesson. 



(Plate IX., fig. 12.) 



Holothuria edulis, Lesson 1830 (22) ; Semper 1868 (38) ; 

 Ludwig 1882 (26), 1887 (29), 1888 (30), 1899 (32) ; 

 Lamport 1885 (19) ; Theel 1886 (42) ; Sluiter 1901 

 (41) ; Koehler 1896 (15) ; Bedford 1899 (2) ; Konings- 

 berger 1904 (18). 



Trepang edulis, Jilger 1833 (14). 



Holothuria fusco-cinerea, Selenka 1867 (37), (non Jager). 



Holothuria signata, Ludwig 1875 (23) ; Lampert 1885 (19), 

 1895 (21) ; Theel 1886 (42). 



.? Holothuria albida, Bell 1887. (5). 



Numerous specimens from the various collections under 

 examination. This is a very common Indo-Pacific littoral 

 form, which is used as beche-de-mer . 



External Characters. — I have been able to examine large 

 numbers of Hving specimens from Ceylon, and they always 

 have a very characteristic appearance. The ground colour of 

 the skin is a bright rose-pink, which may be disguised by 



