ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 475 



occurrence of schizogony in E. coU, and the only well-established case of 

 plnrinucleate vegetative forms leading to schizogony by successive 

 bi-partitions is that of E. ranarum Grassi, cited by Collin, But these 

 cases of schizogony occur only at certain periods of the cycle ; they are 

 not frequent, and they have not been seen by other eminent protozoolo- 

 gists who have studied the species. The plurinuclearity of E. memili, 

 therefore, finds a parallel only among amcebte of the Pelomyxidae group, 

 or among certain terricolous amoebae with a pellicle like A. fihrillosa 

 Greeff or A. alba Greeflf. 



The author promises details of nuclear division and the sporogonic 

 cycle in a later paper. 



Study of Noctiluca.* — Ethel Browne Harvey finds that the specific 

 gravity of Noctiluca is less than that of sea-watei" ; it must have a lower 

 salt-content than the sea-water ; the plasma membrane has the usual 

 semi-permeability towards the balanced salts of sea-water, i.e. permea- 

 bility to water and impermeability to salts ; it can lessen and increase its 

 specific gravity in a regulatory fashion. 



The luminescence requires stimulation ; it comes from granules in the 

 protoplasm ; it requires oxygen ; it is normally a momentary bright 

 flash ; dying animals and anaesthetized animals produce a steady glow ; 

 completely broken specimens glow bat do not flash. 



Angesthetized specimens always give some glow, unlike luminous 

 bacteria whose light-giving power can be completely antesthetized. Ex- 

 periments show that the ansesthetic attacks the mechanism of the 

 utilization of oxygen in the cell, and not the permeability of the cell 

 membrane for oxygen. 



Cycle of Monocystis michaelseni.f— Olga Tolosani has studied the 

 life-history of this Gregariue from the ccelom of Pheretima heterocliseta. 

 In the genital organs there was another Gregarine, probably Stomatophora 

 coronata Hesse. The trophocytes of M. michaelseni were free, the other 

 stages were found in the segmental phagocytic organs where they seemed 

 to flourish. A description is given of the phenomena preceding the 

 purification of the nucleus, the process of purification, the chromatin 

 reduction and the process of division, the formation of gametes, and the 

 occurrence of anomalous encystations. The minute structure of the 

 adult is dealt with. The figures have unusual excellence. 



Sexual Stages of Sarcocystis muris.| — Howard Crawley has studied 

 the life-history of this sporozoon. The spores ingested by a mouse may 

 reach the posterior part of the small intestine within one hour and invade 

 the epithelial cells. Within the lumen the spore changes rapidly. The 

 nucleus becomes larger and more conspicuous, and a distinct nuclear net 



* Proc. Nat. Acad. Sci. U.S.A., iii. (1917) pp. 15-16. 



t Monitore Zool. Ital., xxvii. (1916) pp. 217-22(2 pis.). 



X Proc. Acad. Nat. Sci. Philadelphia, Ixviii. (1916) pp. 2-4.3 (5 pis.). 



