396 THE VOYAGE OF H.M.S. CHALLENGER. 



series decreasing in size downwards, and the supply evidently coming from the genital 

 clefts beneath. In several specimens which I examined, although by no means in all, 

 there were groups of eggs and of young in still earlier stages, free in the body-cavity in 

 the interbrachial spaces. 



" It thus seems that in this case the true ' marsupium ' is a portion of the body-cavity, 

 and that the protection afforded by it is supplemented by the attachment of the young to 

 the surface of the disk, maintained for some time after their extrusion or escape. 



" The process of propagation in Ophiaeantha vivipara differs from most of the other 

 cases described, in the eggs being successively hatched, and the young being found con- 

 sequently in a regularly graduated series of stages of growth. Although I had not an 

 opportunity of working the matter out with the care and completeness I could have 

 wished, I feel satisfied, from the examination of several of the young at a very early 

 period, that in this case no provisional mouth and no pseudembryonic appendages what- 

 ever are formed, and that the primary aperture of the gastrula remains as the common 

 mouth and excretory opening of the mature form. From the appearance of the ovaries 

 and of the broods of young, I should think it probable that this species gives off 

 young in a continuous series for a considerable length of time, probably for some 

 months. 



" I have selected these illustrations of the development of the young of Echinoderms 

 from the egg without the intervention of a locomotive ' pseudembryo ' from a much 

 larger number. As I have already said, I cannot, on account of the unfavourable condi- 

 tions for carrying on such investigations under which the majority of the species were 

 procured, say with certainty that no trace of pseudembryonic appendages or provisional 

 organs exist in any of these instances, but I feel satisfied that none such occurs in Psohis 

 ephippifer, in Hemiaster cavernosus, or in Ophiaeantha vivipara. Neither am I in a posi- 

 tion to state that in these southern latitudes direct development is universal in the sub- 

 kingdom. I believe indeed that it is not so ; for species of the genera Echinus, Strongy- 

 locentrotus, and Amblypneustes run far south, and a marsupial arrangement seems 

 improbable in any of these. It is, however, a significant fact that, while in warm and 

 temperate seas ' plutei ' and ' bipinnariae ' are constantly taken in the surface-net, in the 

 Southern Ocean they are almost entirely absent." 



From Heard Island to the Antarctic Circle and Australia. 



It will doubtless be interesting to navigators to know how the Challenger fared when 

 cruising in the little-known region of the Antarctic and among the ice, therefore the 

 various movements of the ship are here given in detail. 



On the 8th February, at 1 a.m., a heavy sea struck the ship and stove in the two 



