248 THE AQUARIAN NATURALIST. 



only a slender isthmus connects the two halves, and 

 this becomes soon a mere hair-like thread, which, 

 being ruptured, leaves the original animal either in 

 equal halves, or consisting of a greater and lesser 

 portion. 



The duration of this process is very irregular; neither 

 does it seem influenced by size or season, or any other 

 condition. Separation frequently takes place in the 

 night without previous indication ; at other times it 

 may be seen in progress during three or four days. 



The animal seems literally rent asunder, and the 

 intestinal organs, occupying a large portion of the 

 interior of the body, are undoubtedly rent asunder 

 also, so that obviously an internal reproduction must 

 ensue as wonderful as the external reproduction of 

 the arborescent apparatus. 



The spawning of the Holothuria occurs in February, 

 March, April, May and June, when many thousand 

 ova are produced by a single individual. The larva 

 for such we may designate the young progeny on its 

 first escape from the egg resembles a bean-shaped 

 animalcule, having its back convex, while an irregular 

 transverse fissure, answering to what botanists would 

 call the hilum of the bean, indicates the position of 

 the mouth. The margins of this fissure are edged by 

 a ciliated fringe similar to that of the Pluteus de- 

 scribed in the last chapter. In the course of its 

 growth the margins of the larva and the corresponding 

 parts of the fringe are thrown into numerous lateral 

 processes, giving it a scolloped appearance. By slow 

 degrees, the creature next assumes a barrel shape ; 

 the former mouth of the larva becomes obliterated, 



