REPORT ON THE GENUS ORBITOLITES. 15 



can be plainly discerned, which correspond in size and appearance with the nuclei described 

 by Hertwig in the fresh-water monothalamous Microgromia,^ and subsequently in 

 Spiroloculina, Globigerina, Rotalia, and other marine polythalamous forms.^ The very 

 irregular distribution of these nucleus-like bodies shows that they cannot have any 

 particular local function. In the specimen here figured (PI. 11. fig. 1) two of the outer 

 half-whorls of the Spiroloculine centre (shown on a larger scale at h, h, b', h', fig. 4) are 

 crowded with them, while in a single chamberlet (c) of one of the interior zones there are 

 as many as five. Elsewhere they present themselves with less frequency, only one or 

 two occurring in any single chamberlet {d, d, d), and a large proportion of the 

 chamberlets being entirely devoid of them. Their diameter is about jY^g^th of an inch. 



The substance of the sarcodic bodies of Orbitolites duplex and Orhitolites complanata, 

 on the other hand, consists in great part of an aggregation of spherical corpuscles about 

 2 5\)o th inch in diameter, as shown under a power of 120 diameters in PL V. fig. 3, and 

 magnified 180 times in fig. 16. These corpuscles might be easily taken for cells ; but 

 not only does a careful examination of them fail to bring into view either nucleus or 

 limitary membrane, but they are found, when subjected to pressure, to break-up into a 

 multitude of separate rounded granules, of extremely pellucid aspect, from -g^y^th to 

 12 ^^^ io-ch. in diameter. Sometimes the spherical corpuscles are very closely packed 

 together, especially in the primordial segment ; in other instances there are considerable 

 spaces between them, as shown in PI. V. fig. 16. 



The whole sarcodic body of Orbitolites duplex has a reddish tinge, which is most 

 decided in the primordial and circumambient segments, and in the inner annuli of sub- 

 segments. And in these I can generally observe, more or less distinctly, a limiting 

 membrane (PI. V. fig. 5), sometimes rather deeply tinged with red, which is probably 

 of a chitinous nature. On the other hand, scattered irregularly in difi'erent parts of the 

 disk, certain bodies present themselves (PI. V. figs. 4, a, b, c, 15, 17), which have a much 

 more distinct cellular nature, having a very thick (apparently cellulose) cell-wall, and a 

 deep red endochrome. These I am strongly inclined to regard as vegetable. Their 

 diameter (usually about ^^th inch) is much too great to allow them to have passed 

 through the marginal pores in their present condition ; but as there are now several well- 

 established cases of parasitic vegetation, I cannot think it impossible that the germs 

 of these cells found their way in from without, and have undergone their sub- 

 sequent development in the places they now occupy. The living specimens of the " duplex" 

 type were for the most part obtained in the 18 fathoms' dredging on the bank of the Fiji 

 reef ; and it does not seem improbable that their sarcodic bodies derive their red hue from 

 zoospores or other particles of the Rhodosperm AlgcB inhabiting that zone, which they may 

 take-in as food. For the sarcodic bodies of Orbitolites compAanata, whose living specimens 



1 Archiv.fUr MikrosJcop. Anat., Bd. x. Supplement-heft. 

 - Jeiiaisdie Zeitschrift, Bd. ix.-xi. 



