470 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the working of the cubic centimetre chamber of Kolkwitz for counting 

 the upper limit of production is discussed in detail. 



Fresh-water Species of Ceratium.* — J. Woloszyriska writes on the 

 fresh-water species of Ceratium, G hirundinella, G. cornutum, G. cur- 

 virostre, and C. brachijceros. The stability in the length of the cells in 

 the three latter species is to be noted. The length of G. hirundinella 

 varies between 100 and 400 fx. G. cornutum is regarded as a very old 

 form. The peculiar characteristics of each species are given in detail, 

 and also set forth in a key. The geographical distribution is treated, 

 and the genealogical origin of the species is indicated by a diagram. 

 The author regards the development of the third posterior horn in 

 C. hirundinella as a form of adaptation in order to increase its floating 

 surface and its swimming capacity. 



Flagellatse and Cyanophyceae.f — A. Pascher describes a symbiosis 

 occurring between Flagellates and Cyanophycege, the alga being situated 

 on or in a gelatinous envelope of the principal organism. The species 

 of alga was different in each of the four examples investigated. The 

 author proposes the name of syncyanosis for symbioses of this character. 

 They appear to be specialized types of combinations between blue algse 

 and various organisms which possess gelatinous envelopes, such as have 

 been known for some time among the higher blue algae. Two new 

 symbioses are described : between Anabsena sp. and a small net-forming 

 species of Chroococcaceas ; and between a green alga and one of the 

 Charnaesiphonaceae. Points of physiology are discussed. 



Flagellum of Euglena.J — J- Burton writes a short note on a 

 phenomenon which has been mentioned by a few authors, but not 

 explained satisfactorily — the little disk attached to the distal end of the 

 flagellum of some Euglena3. The author believes it to be a coil of the 

 flagellum, since he has seen similar loops or " kinks " at the sides as well 

 as at the end. They appear to be only visible in a flagellum which has 

 been cast off. 



Eudorina elegans.§ — W. Conrad publishes observations on the 

 morphology of Eudorina eleg an s Ehrenb. The cells are always perfectly 

 spherical, and their diameter varies from 15-25/x. The small hyaline 

 prolongation described by Goebel was not seen. The cells contain at 

 least one pyrenoid, the mature cells often five to nine. The nucleus is 

 globular, almost central. The stigma has the form of a watch-glass 

 and is a brilliant red. Its size decreases in proportion as the rings of 

 cells move away from the apical to the posterior pole. It takes no part 

 in cell-division. There are two cilia, which protrude, across a tube 



* TCosmos (Lemberg, 1913) pp. 1262-80 (1 pi. and figs.). See also Bot. Cen- 

 tralbl., cxxvi. (1914j pp. 90-2. 



t Ber. Deutsch. Bot. Gesell., xxxii. (1914) pp. 339-52 (1 pi.). 



% Joum. Quekett Micr. Club, xii. (1914) pp. 291-4 



§ Rec. Inst. Bot. Leo Errera, ix. (1913) pp. 321-43 (13 figs, in text). See also 

 Bot. Centralbl., cxxvi. (1914) p. 13. 



