ZOOLOGY AND BOTANY, MICROSCOPY, ETC. L65 



up to a certain point true cysts. The author has tried to cultivate bhem, 

 but without success. It is probable that P. Westii, which disappears in 

 winter, possesses like P. aciculiferum thick-walled cysts ; but up to tin 

 present only these curious zoospores with a mucilaginous sheath have 

 been found, which behave like floating cysts. This is probably the 

 result of the exclusively planktonic life of P. Westii. 



Alternation of Generation in Algae.*— C. Janet writes on the 

 sporophyto-gametophytic alternation of generations in Alga?. The sub- 

 ject is treated under the chapter headings : I. Holophyte ; II. Ortho- 

 phyte (1) alga? of which the orthophyte presents no sporophyto-gameto- 

 phytic alternation of generations {Eudorina, Volvox, Diatomacea?, Fucus) ; 

 i.2) alga? of which the orthophyte does present such alternation (tetra- 

 spores of polysiphonous Rhodophycea?, Spirogyra) • (:i) Clothrix zonata. 

 an alga representing the ancestral form in which was established sporo- 

 phyto-gametophytic alternation. 



Saprophytic Aigse.f — S. Mendreka has studied the transformation 

 of green alga? into saprophytes, by supplying them with their necessarv 

 carbon in the form of sugar or other organic substances. The species 

 under observation were Clorothecium saccharophilum, Ghlorella proto- 

 thecoides, and especially Gldoreila variegata. The methods and formula? 

 employed are described. 



Flagellates Inhabiting Plankton Diatoms.^ — K.Rouppert describes 

 and figures a new species of Salpingoeca, growing on G/mtoceros 

 Zachariasi in a backwater of the Weichsel near Ciechocinck in Poland. 

 It is minute, cpuite globular, seldom slightly oval, 5-6/x in diameter, 

 elongated above into a short, sharply truncate cylindrical neck, 3/u. 

 long and 2-3 broad. A protoplast of globular form completely fills 

 the upper part of the envelope ; the nucleus is in the front end. The 

 author also describes his examination of S.frequentissima Lemm. which 

 confirms the results of Bachmann and Lemmermann on structural 

 details. The swarm-spores are described in detail and figured. 



Ceratium hirundinella.§ — E. Malinowski has confirmed the relation 

 between the form of the nucleus and the form of the cell. Elongated 

 individuals possess a globular nucleus or one more or less drawn out 

 axially to the cell. On the other hand, the shorter individuals have 

 a nucleus broader than long. The length of the horns stands also 

 in close connexion with the breadth of the cells. These facts are 

 set forth in tabular form and are also shown in figures of individual 

 specimens of C. hirundinella. 



* L'alternance sporopbyto-gametopbytique de generations chez les algues. 

 Limoges, 1914 (7 figs, in text). See also Bot. CentralbL, cxxvi. (1914) pp. 410-11. 



t Bull. Soc. Bot. Geneve, v. (1913) pp. 150-80. 



% Kosmos, Lemberg, 1913, pp. 1608-15 (2 pis.). See also Bot. CentralbL, cxxvi. 

 ( n6T ) p. 411. 



§ Kosmos, Lemberg, 1913, pp. 1329-43. See also Bot. CentralbL, cxxvi. (1914) 

 p. 411. 



