C. The _gelatinous spheres_ of various sizes, found in the endoplasm of the Radiolaria, agree in their reactions (especially in staining by certain reagents) with the common extracapsular jelly of the calymma, and are hence distinguishable both from the true (coagulable) "albumen sphere," and from the ordinary watery vacuoles.
D. The _alveoles_, which are only accurately known in the case of certain large monozootic #Collodaria#, but which also seem to occur in the central capsule of other remarkably large Radiolaria, were described in my Monograph in the case of _Thalassolampe margarodes_ and _Physematium mülleri_, under the name "intracapsular alveolar cells" (1862, pp. 77, 254, 257). They are not, however, true nucleated cells, and the body described as a nucleus is not such in reality. Nevertheless these large hyaline spheres do possess a special envelope, as I have recently convinced myself by the examination of ruptured central capsules of _Thalassolampe maxima_, _Thalassopila cladococcus_, and _Physematium atlanticum_ (Pl. 1, figs. 2, 3). The central capsule of these #Collodaria# becomes distended to most unusual dimensions (2 to 12 mm. in diameter) by the great development of these large hyaline vesicles, each of which measure from 0.1 to 0.5 mm. in diameter.