HOLOTHTJRIOIDEA OF THE INDIAN OCEAN. 63 



more numerous pedicels which are irregularly disposed. The 

 anus is surrounded by a ring of papillae. 



Internal Structure. — Selenka speaks of the calcareous ring 

 as being large, but in the specimen I have examined it is very 

 small in comparison with most Holothurians. The allied 

 form Holothuria lubrica has a large calcareous ring. There is 

 a single Polian vesicle 4 mm. long and a large stone canal 

 arising from the right side of the dorsal mesentery. This 

 stone canal is over three times as long as the Polian vesicle. 

 Cuvierian organs are present. 



Spicules. — -These consist of flattened plates, which in their 

 complete state have a solid longitudinal axis bordered by 

 numerovTs small holes. The holes along the course of the 

 longitudinal axis frequently break down and produce perhaps 

 the commonest type of spicules, which is a long rod having 

 swollen ends which are perforated. All stages between these 

 two extremes are seen. The spicules vary from 56 [jl to 84 u, 

 in length, with a mean length of 66 [k. 



General Distribution. — This form has a world-wide distribu- 

 tion in tropical and sub-tropical waters, and is found in the 

 Pacific, Indian, and Atlantic Oceans. 



HoLOTHUEiA LUBRICA, Selenka. 



(Plate VIII., fig. 9.) 



Holothuria lubrica, Selenka 1867 (37) ; Semper 1868 (38) 

 Ludwig 1882 (26), 1887 (28), 1898 (31), 1899 (32) 

 Lampert 1885 (19), 1896 (21) ; Theel 1886 (42) 

 Sluiter 1901 (41) ; Koehler & Vaney 1908 (17). 



I have one specimen, collected by Professor C. Ishikawa on 

 Japanese waters. This is labelled Holothuria lubrica var. 

 moebii, but it differs in no way from Holothuria lubrica and 

 does not possess the essential characters of Holothuria moebii. 



External Characters. — The spirit specimen measures 50 mm. 

 in length and 20 mm. in breadth, but it is much contracted 

 and wrinkled. It is with difficulty that the ambulacral 

 appendages, consisting of pedicels below and papilltB above, 



