HOLOTHURIOIDEA OF THE INDIAN OCEAN. <S7 



HoLOTHURiA SCABRA, Jager. 

 (Plate XIII., fig. 22.) 



Holothuria scabra, Jager 1833 (14) ; Brandt 1835 (8) ; 

 Semper 1868 (38) ; Haacke 1880 (12) ; Liidwig 1882 

 (26), 1883 (27) ; Lampert 1885 (19) ; Theel 1886 (42) ; 

 Sluiter 1901 (41) ; Koningsberger 1904 (18) ; Koehler 

 & Vaney 1908 (17) ; Pearson 1910 (34), 1910 (35). 



Holothuria tigris, Selenka 1867 (37). 

 Holothuria cadelli, Bell 1887 (5). 

 Holothuria gallensis, Pearson 1903 (33). 

 There are numerous specimens in the collections under 

 examination. 



External Characters. — The body is comparatively short and 

 stout. The two ends are flattened. The body is covered 

 with minute papillae, which are irregularly scattered and are 

 more abundant on the trivium than on the bivium. This 

 species probably shows greater colour-variation than any 

 other Holothurian. The bivium may be black, black with a 

 few yellowish- white streaks, or black wdth broad transverse 

 white bands. The black inay vary in intensity, and is 

 frequentl}'- replaced by gray. The trivium is of a light yellow 

 colour, so that there is a marked distinction between the two 

 surfaces. On the yellow ground may be seen numerous small 

 gray patches, which mark the position of the papillae. Each 

 papilla is grayish in colour and surrounded by a gray circle. 

 In the extreme cases the gray patches join together to form 

 an irregular mass, broken up by lighter markings. There are 

 twenty tentacles. 



Internal Structure. — The calcareous ring is normal. The 

 Polian vesicles vary in number. In one freshly-killed specimen , 

 225 mm. long, there were three Polian vesicles. The first was 

 40 mm. long and arose in the left inter-radius of the trivium. 

 The second was 15 mm. long and arose on the left radius of the 

 bivium. The third was 110 mm. long and arose near the 

 dorsal mesentery. The single stone canal is small and 



