564 PROF. F. J. BELL ON HOLOTHUROIDS. [Dec. 2, 



After treatment with strong hydrochloric acid the alcoholic solution 

 becomes yellowish in reflected as well as in transmitted light : it 

 becomes dirty yellow on the addition of ammonia, and throws down 

 a turbid precipitate which gradually became more and more flocculent ; 

 this was at first of a dirty white colour, but became yellow on 

 standing for a short time. Just as in the case of antedonin, the 

 precipitate from the ammoniacal solution was very abundant, but, 

 unlike it, the solution was much less strongly coloured after the 

 deposition of the precipitate. After filtration the precipitate was 

 left as a yellowish powder, which was insoluble in water or alcohol, 

 but dissolved pretty readily in acidified alcohol ; in this point it 

 again resembles antedonin. After solution in acidified alcohol, the 

 precipitate became of a faint yellow colour, but did not give a green 

 reflection. Further addition of alkaline reagents to the filtered 

 alcohol produced a further precipitate. 



On the whole, then, it is clear that there is in Holothuria nigra 

 a colouring-matter of the same character as antedonin : but if the 

 body now under consideration has distinctive absorption-bands, they 

 are in the Cotton-Spinner obscured by another colouring-matter, 

 which is especially richly deposited at the distal or attached end of 

 the Cuvierian tubes, and which readily, after solution in alcohol, 

 stains the human skin yellow. The viscera are at least, as much as 

 the integument the seat of the antedonin-like colouring-matter, for 

 spirit which has only come into contact with the viscera is as 

 distinctly yellow and green as is that in which the whole of the 

 body is preserved. Here again, then, we have an example of that 

 diffusion of colouring-matter through the tissues of an Echinoderm 

 to which Prof. Moseley has, in the paper cited, already directed 

 attention. 



The fact that the threads of the Cuvierian organs swelled out in 

 water led me to try and see if I could detect the presence of mucin. 

 No response, however, in that direction was given by the ordinary 

 experiment of adding to the water, in which some tubes had been 

 standing for more than ten days, solid chloride of sodium, nor did I 

 get any precipitate with acetic acid. Shortly after death the threads 

 are hardly at all sticky, but after a few days' treatment with strong 

 salt solution they become much more so ; the threads are quite well 

 preserved from putrefaction, even in hot weather, by being placed in 

 strong salt solution : a solution not carefully sheltered from atmo- 

 spheric air harboured but few bacteria after being some ten weeks 

 in a not over-clean room. If, however, the threads are left in sea- 

 water or exposed to the air they rapidly undergo putrefaction, and 

 give off a more offensive odour than any other decomposing animal 

 substance with which I am acquainted. 



In one specimen forwarded to me the tubes had evidently been 

 protruded in a natural manner : a compact strand of about an inch 

 in length and one fifth of an inch in thickness protruded from the 

 cloacal orifice ; this at its free end was frayed out into a large number 

 of comparatively fine tubes which were attached to the seaweed in 

 the water, and extended over about two inches in breadth. As I 



