54 ECHINODERMATA. 



originally, or detached subsequently. Four months after the present 

 copious spawning, eighty or ninety ova, pure white to the naked eye, 

 though exposing a dark central nucleus, were found, principally on a leaf 

 with which the parent had invested itself. They were imbedded in a 

 transparent gelatinous substance, whence all were detached on changing 

 the water, and floated with nearly the same specific gravity. 



Notwithstanding every precaution to preserve it on both occasions, 

 none of the spawn proved fertile, which is to be the more regretted, as 

 the early history of the Holothuria, and particularly the progTessive evo- 

 lution of the original organization, is yet unexplained. 



Regarding the latter, there are probably some equivalent data, indi- 

 cating the uniform process which may guide the first evolution of the ten- 

 tacula, and that attending their regeneration. All the parts are succes- 

 sively developed. This specimen had undergone an extraordinary 

 mutilation, which was not fatal. The renovating organs were much 

 advanced in May of the second year of its custody, which had then con- 

 tinued about eighteen months : and in the course of the succeeding 

 months, when nearly in its greatest vigour, about twenty-four lateral 

 branches sprung from each stem of the tentacula, the higher being 

 merely twigs ; the others abbreviated in proportion to their distance 

 from the cyUnder. The second on the stem of some was longer than 

 the first or lowest. Towards the latter part of June, flitting crimson 

 patches occasionally stained the whole arborescent apparatus ; and in 

 the earlier days of July, the reddish colour was more predominant than 

 previously. 



From the first of September the size of the animal diminished. 

 Though displayed on the 8th, and sometimes subsequently, the branches 

 manifested less vigorous action. Their scope was confined. Yet distension 

 of the body to almost its natural size, attended renewal of the w^ater on 

 the 13 th ; the antennulae were in feeble operation ; also the cylinder 

 protruded feebly, with the tentacula reduced to a tuft, as if too weak 

 for evolution ; and the whole apparatus was soon withdrawn. But the 

 body became distended and peUucid as before, without displaying the 

 organs. 



