96 ECHINODERMATA. 



After surviving six or seven months, this specimen perished acci- 

 dentally. 



During the season of propagation, the rays of the Asterias glacialis 

 are distended by a great ovarium. This, perhaps, may be considered as 

 divided into five parts, one occupying each ray ; each part, consisting 

 of two triangular lobes of unequal size in every ray, with subordinate 

 parts, also triangular, and resembling clusters of currants or grapes. To- 

 wards the end of May they are seen to be an accumulation of speckled 

 capsules, which bursting, discharge a quantity of molecules, like dust, 

 falling to the bottom of the vessel. Fig. 6. 



The capsules farthest advanced belong to the larger portion of the 

 roe, that towards the body of the animal which seems the first to origi- 

 nate. A solid nucleus within an integument is discovered in each of the 

 molecules discharged from the capsule. The spawn is long of attaining 

 maturity ; the lobes represented, fig. 6, being only in progress in the 

 end of April. A month, or perhaps two, had still to elapse before the 

 discharge of the ova. Fig. 7. 



This species is extremely subject to mutilation of the rays. It is 

 constantly found with one or more in progress of reproduction. Muti- 

 lation does not seem incidental to age, size, or season. But to shun re- 

 petition, I shall reserve a few observations on the subject for the follow- 

 ing paragraph. 



I am ignorant whether specimens, originally white, invariably 

 change their colour, having witnessed its permanence in some of con- 

 siderable size, as previously said. 



PLATE XVI. 



Fio. 1. Asterias glacialis The Northern Sea-star, adult. 



2. Young specimen. 



3. Young specimen, originally white. 

 4. Ray of fig. 3, enlarged. 



5. Fig. 3 represented four months later than previously, being now 



purple. 



6. Lobes of spawn. 



7. Ova enlarged. 



