ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



643 



light. The glass vessels in which they were kept were red at the 

 side turned towards the light, whilst the opposite side remained 

 colourless. If the vessel was hlackened so that light could only 

 penetrate through a small orifice, the 3tonas abandoned the dark 

 regions and concentrated themselves in the light. This is not the 

 only red organism that shows this attraction to light ; and this cir- 

 cumstance has led to its being confounded with an Alga which has 

 the same colour, and is deposited in the form of large pellicles on the 

 walls of vessels exposed to daylight. Claythrocystis roseo-persicina 

 is thus often found associated with Monas Okenii. 



Oviform Psorospermise or Coccidia.* — A. Schneider gives the 

 following as a provisional classification of the Psorospermiae : — 



Tribe I. The whole of the contents of the cyst are converted into 

 a single spore. Monospore^e. 



a. Spore enclosing a definite number of corpuscles. Oligozoids. 



Corpuscles four in number. Orthospora. 



b. Spore enclosing an indefinite number of corpuscles. Polyzoids. 



Eimeria. 

 Tribe II. Contents of cyst becoming converted into a constant 

 and definite number of spores. Oligospore^:. 



A. Only two spores. (Disporeae.) 



a. Corpuscles of the spores in definite number. Cyclospora. 



b. Corpuscles of the spores in indefinite number. Isospora. 



B. Four spores. (Tetrasporeae.) Corpuscle, one. Coccidium. 

 Tribe III. Contents of cyst becoming converted into a great 



number of spores. Polyspore^:. Klossia, Benedenia. 



The author then describes three new genera (Orthospora, Cyclospora, 

 and Isospora), with three new species, and two other new species of 

 previously known genera. 



BOTANY. 



A. GENERAL, including Embryology and Histology of the 

 Phanerogamia. 



Development of the Embryo and Embryo-sacf — M. Treub states 

 that Peristylus grandis furnishes an excellent demonstration of the 

 fact previously recorded by him J that in the Orchideae the suspensor 

 performs the function of a nutritive organ for the embryo. Some 

 time after fertilization the embryo-sac is found to contain a small 

 suspensor composed of a row of two or three cells. The upper 

 portion of this soon grows rapidly, and finally protrudes beyond the 

 exostome, putting out digitate much-branched protuberances, which 

 creep over the funiculi and placentae, robbing them of their non- 

 nitrogenous contents for the benefit of the embryo ; the cells of the 



* Arch, de Zool. Expe'r. et Gen., ix. (1881) pp. 387-404 (1 pi.), 

 f Ann.du Jardin Bot. de Buitenzorg, iii. (1882) pp. 76-87 (3 pis.). See Bot. 

 Centralbl., x. (1882) p. 356. 



% See this Journal, iii. (1880) p. 474. 



