HOLOTHURIA. 03 



tuse extremities ; some are folded double ; and in a great number, if 

 not in aU, the ova are arranged in more than a single row, Plate XI., 

 fig. 9 : end of a rope, enlarged, fig. 10 : extremity of ropes, enlarged, 

 fig. 11. 



When preparing to shew a naturalist of my acquaintance such 

 objects, he assured me that no one had ever seen the ovum of a Holo- 

 thuria. Certainly very little is said of it. 



In all instances, excepting two, the ova have been green of different 

 shades, or yellowish. The ovarium tended to purple in one, it was red 

 in the other. When protruding by an accidental rupture, it resembles 

 a mop or brush. 



The specimen Plate VIII., fig. 2, lost the whole arborescent appa- 

 ratus within two or three days of its capture. Nevertheless it seemed 

 still plump and full of spawn. In ten days a large ovarium, composed 

 of numerous ropes, protruded like a brush, the ova irregularly distributed 

 in one, two, or three rows, all of a greenish-yellow. Probably the ropes 

 are in reality long and folded, they have some appearance of being 

 tubular, which may be deceptive. In the course of extent they are of 

 unequal diameter. The ova are minute, spherical, or slightly ovoidal, 

 consisting of a nucleus within albuminous matter. A few have oc- 

 curred of a yellow colour ; but green, greenish, or greenish -yellow, is the 

 common hue, Plate XI., figs. 5, 6. 12, 13, 14, 15. Their natural aspect 

 appears in fig. 12. 



Spawning has ensued in February, March, April, May, and June, 

 when many thousand ova have been produced by single individuals. 



But to my great concern, spite of the most careful treatment, none 

 have ever proved fertile. On no occasion having been from large speci- 

 mens, I was almost induced to conjecture that the Holothuria must be 

 of a certain age before the spawn is prolific, — a fact not likely, I confess, 

 l)ut which is to be ascertained only by future observation. 



It would be very interesting to behold the development of the 

 young from the ovum, and to follow the progressive evolution of the 

 parts. But I have not been so favoured. It is by the merest chance 

 that smaller specimens can fall into the hands of the observer. From 



