10 K. M. WOODCOCK. 



the animals clirectl\\ As soon as they were touched, however^ 

 they withdrew their tentacles into the buccal cavity, and 

 closed this tightly up, leaving nothing visible extei'ually. They 

 evinced, moreover, a decided reluctance to be turned on their 

 backs, which was necessary since the bnccal cavity is slightly 

 ventral, or at any rate normally turned veutrally. Sometimes 

 after holding a Holothuriau gently, yet firmly, with my hand, 

 often so long that my arm was quite cramped, it would unfold 

 its tentacles and allow me a beautiful view of its mouth. I 

 then cautiously steered a tiny piece of blood-vessel with a 

 cyst attached^ to the open mouth. I have seen it pass in and 

 apparently fall some distance down the gullet, but it was 

 nearly always pushed up again and out into the buccal cavity, 

 usually to be lost among the tentacles. Whether this expul- 

 sion took place actively or passively I am not quite certain, 

 although I think probably the latter, since there generally 

 seemed to be a current alternately of inspiiation and expira- 

 tion when the animal was not feeding. If the cyst stayed in 

 as long as I retained my hold, it invariably fell out Avlien I 

 allowed the animal to resume its normal position. Now and 

 again, by way of diversion, the Holothurian would suddenly 

 eject the whole contents of its body about my hnnd, which I 

 had then to extricate from the Cuvierian organs. 



I also tried mixing some cysts with particles of sand and 

 mud, making a smtdl accumulation on the floor of a dish and 

 placing the animal with its buccal cavity near to it. The 

 heap would be disturbed by the tentacles, to one of which a 

 cyst, or part of one, might even adhere, only to be brushed 

 off by something a moment later; in short, the Holothuriau 

 would not eat to order. Once or twice I thought a few spores 

 might possibly have succeeded in getting well down and 

 staying there, and the animals were killed alter a certain 

 time had elapsed. I fixed and sectioned different portions of 



^ Since there is no true cyst-wall to a ripe cyst of C. irregularis (ilic 

 tliiu cyst-nicnihraiie liavinj; before lliis broken down and disappeared), tlic 

 spores are only lield logeliier by the delicate evai,'inaled cjiil helium of the 

 blood-vessel. 



