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



sarcodic body has been preserved in alcohol, the cavities of several outer zones are quite 

 empty, whilst those of the " nucleus " and inner zones are quite filled. For the shrinkage 

 of the sarcodic substance, produced by the corrugating action of the spirit, has drawn the 

 substance of the peripheral annuli towards the central portion of the disk ; and this could 

 not happen, but for the entire absence,— ;^?'s«, of any attachment of the body to the walls 

 of the cavities that enclose it, and, second, of any resistance to the complete change of 

 form it must undergo, to allow the passage of the substance that occupies the chamberlets 

 of the outer zones, through the narrow connecting passages which lead to the inner cavities 

 of the disk, in which it so completely fuses with their own body-substance, as not to 

 present the least appearance of heterogeneousness. 



This absence of differentiation is further made apparent by the extraordinary 

 reparative power possessed by every form of Orhitolites ; not only losses of substance to 

 any amount and in any part of the disk being made good, but even a small detached 

 peripheral fragment having the power to develop a new disk, as shown in PI. I. figs. 

 6, 7, and in PL VIII. figs. 2-10. It is clear that connection with the central "nucleus" 

 is not in the least degree requisite for the continued growth of the peripheral part ; and 

 it is also clear that after the cyclical stage of growth has been once attained, the reparative 

 process is entirely directed to the reproduction of the complete discoidal form. This is 

 obviously to be explained by an extension of the homogeneous sarcodic body-substance 

 around the whole maroin of the frag-ment, so as to form an anuulus which buds-off a new 

 and complete cu'clet of chamberlets. 



Thus, we have every reason to believe, each sub-segment of the sarcodic body 

 precisely repeats the rest, and would be equally capable of maintaining its own existence 

 if detached from the disk of which it forms part. It is clear that the inner portion of the 

 disk can only be nourished through the intermediation of the outer, as it has no 

 communication with the medium around, except through the marginal pores ; and from the 

 analogy of other Ehizopods there is strong reason to believe that diuing life there is a 

 continual flow of semi-fluid protoplasm from one part to another, so that any nutrient 

 material obtained by the peripheral annulus from without is speedily diffused through the 

 entire mass. 



Owing to the smallness of the number of spirit-specimens of the deep-sea t}^e, 

 Orhitolites tenuissima, that have come into my po.ssession, 1 have not thought it well to 

 decalcify any one of them for the examination of its very attenuated body. But the 

 superficial lamellae which close-in the chamberlets are so transparent, that the general condi- 

 tion of the protoplasmic substance which occupies them can be pretty clearly made out. 

 This seems to have the dark olive-green hue, which is commonly met with in the sarcodic 

 body of the " arenaceous " deep-sea Foraminifera ; and it does not present the corpuscular 

 aspect which I shall presently describe in the sarcodic bodies of Orhitolites duplex and 

 Orhitolites coniplanata. But in one of these specimens several nuclear-looking bodies 



