HOLOTHURIOIDEA OF THE INDIAN OCEAN. 57 



The mouth is ventral and is surrounded by 20 tentacles. 

 The anus is slightly dorsal. It is five-rayed, and surrounded 

 by five groups of papillae. 



Internal Structure. — Internally this species resembles H. 

 marmorata. The form of the calcareous ring is similar in both 

 species. There is a single Polian vesicle and one stone canal. 

 The right respiratory tree, which extends to the anterior end 

 of the body, is larger than the left. The Cuvierian organs are 

 not present in the specimen under examination, although thej'^ 

 have been recorded from this species. 



Spicules. — The deposits in the superficial integument are 

 hardly to be distinguished from those of H. marmorata. The 

 deposits in the deeper layers are, however, wanting in H. argus. 

 The pedicels are supported by two kinds of spicules. First 

 large rods generally perforated at both ends and 200 ^ in 

 length. There are also smaller irregular rods, often H-shaped, 

 about 40 [K in length. 



General Distribution. — Similar to that of H. marmorata. 

 The latter species, however, is more abundant than H. argus. 



HoLOTHURiA viTiENSis, Sciiiper. 



(Plate VII., fig. 6.) 



Holothuria vitiensis. — Semper 1868 (38) ; Lampert 1885 

 (19) ; Theel 1886 (42) ; Sluiter 1901 (41). 



Holothuria tenuissitna . — Semper 1868 (38) ; Ludwig 1882 

 (26) ; Lampert 1885 (19) ; Theel 1886 (42) ; Sluiter 

 1887 (39), 1901 (41); Pearson 1903 (33) ; Koehler & 

 Vaney 1908 (17). 



Holothuria similis. — Semper 1868(38) ; Lampert 1885(19) ; 

 Theel 1886 (42). 



Holothuria koellikeri. — Semper 1868 (38) ; Lampert 1885 

 (19) ; Theel 1886 (42) ; Ludwig 1887 (28). 



Holothuria Clemens.— Ludwig 1875 (23) ; Lampert 1885 (19) ; 



Theel 1886 (42). 

 I 6(5)13 



