20 Prot . 
XVIII. PROTOZOA. 
Schaudinn (191) discusses the life-history of Oalcituba polymorpha 
describing the passage frorri plasmodial forms to those having distinct 
calcareous tests. The nuclear division is traced step by step, numerous 
nuclei being eventually produced from the division of the single 
nucleus. 
Stokes (207) giyes an account of the Infusorian Vasicola annulata } 
the only species of this genus having a brackish-water or marine habitat. 
2. Embryology, 
Balbiani (4) gives an account of karyokinetic changes observed in the 
nucleus, during the process of gemmation in Spirochona gemmipara. 
Beard (6) discusses and supports an antithetic alternation of genera- 
tions and spore-formation, with reduction in the Infusoria. 
Chapman (BO) figures an embryo of Amphistegina racliata occurring in 
one of the peripheral chambers of the adult shell. 
Clarke, J. J. (35), describes the mitotic changes, resulting in direct 
segmentation, observed in Coccidium oviforme. 
Keuten (113). The karyokinesis of Euglena must be regarded as a 
simple intermediate stage between direct and in lirect nuclear division, the 
chromatic substance showing mitotic relationships, whilst the persistence 
and division of the nucleolus recall direct division. 
Labbe (118) regards the nucleus in the Protozoa as homologous with 
that of the cell of the Metazoa , and it is only in the ciliated Infusoria 
that two nuclei occur which are distinct in function ; in these the division 
is abnormal, due probably to physiological causes. 
Lauterborn (121) regards the nuclear division in Oeratiim hirundinella 
neither direct or truly karyokinetic, but, as in the macro-nucleus of 
the ciliate Infusoria , of an intermediate character. 
Mitrophanow (154) observes that the nuclear division in the 
Sphcerozoa ( Radiolaria ) is truly indirect, but of a very simple character. 
Schaudinn (192) describes Amoeba binucleata , the nuclei in which both 
act as one. The nuclear division is commonly mitotic, but direct nuclear 
division also yields individuals capable of propagating themselves. Other 
methods of nuclear division also exists. 
3. Physiology and Biology. 
Brandt ( 1 1 ) discusses the floating, sinking, and rising of Radiolaria , 
especially the Sphcerozoa and Collides. It is shown that sinking and 
rising are intimately associated with disappearance and re-appearance of 
vacuoles. 
Eberlein (57) believes the ciliate Infusoria present in the stomachs of 
Ruminants to be helpful in changing cellulose into materials more 
capable of assimilation by the host. 
