HOLOTHURIOIDEA OF THE ESTDIAN OCEAN, 185 



AcTiNOPYGA MAiTRiTiANA (Quov & Gaimard). 



(PI. XXIX., fig. 8.) 



Holothuria mauritiana, Quoy & Gaimard 1833 (21). 



Mulhria mauritiana, Selenka 1868 ; Ludwig 1882 (14), 



1887 (15), 1888 (16), 1899 (17) ; Lampert 1885 (10), 



1889 (11) ; Theel 1886 (26) ; Sluiter 1887 (24), 1901 



(25) ; Koehler & Vaney 1908 (9) ; Pearson 1910 (29). 



MuUeria varians, Selenka 1867 (22). 



Actinopyga mauritiana, BeU 1887 (3) ; Bedford 1898 (1), 



1899 (2) ; Pearson 1903 (18) ; Fisher 1907 (5). 

 This species is represented in most of the collections under 

 examination. It is universally distributed throughout the. 

 Indo-Pacific, and is perhaps the commonest species of Act- 

 inopyga. 



External Appearance. — This species is subject to much 

 variation in colour. The commonest type is coloured 

 chocolate -brown on the bivium and yellowish- white on the 

 trivium, the two being distinctly separated, so that the white 

 trivium forms a kind of sole. Sometimes the papillae in the 

 bivium are surrounded by j^ello wish- white rings. Occasionally 

 these rings coalesce to form irregular patches. In several 

 specimens I have examined there is no clear separation of 

 colour of the Hghter trivium from the darker bivium, the 

 transition from the one to the other being gradual. In a few 

 instances there is very little brown on the bivium owing to 

 the yellow rings around the papillae being extremely numerous. 

 In fact, every stage of colour is represented between the two 

 extremes, on the one hand the form in which the hmits of the 

 brown bivium and yellowish-white trivium are very clearly 

 defined, and on the other the form in which brown is mottled 

 on a yeUow ground, both on the dorsal and ventral surfaces. 

 There are usually twenty-five tentacles present. The five anal 

 teeth are smooth and are of medium size. This species grows 

 to a length of over 400 mm. 



The ambulacral appendages consist of papillae on the bivium 

 and true pedicals on the trivium. The latter are more closely 



