ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 73 



Note on a New Alg^a, Leptobasis caucasica mihi, followed by a 

 Critical Revision of the Genus Microchsete Thur. — A. A. Elenkix 

 {Bull. Jard. Imp. Bot. Piprre Ic Grand, 1!)15, 15, 5-22, 14 figs. ; see 

 also Bot. Centralhl., liUS. 137, 151-2.) This paper is written in 

 Russian, with a French resume. A new species of Cjanophjceaj is 

 described from the environs of Gagry in the Caucasus, found in 1912 

 on stones in a river. It much resembles Mkrochsete striatida Hy, but is 

 distingiiished by certain pronounced characters. The author has made 

 a special study of the genus Microchsete, and is of the opinion that the 

 species should be divided into three groups, which he considers distinct 

 genera : — (1) Microcli.sete (Thur. p.p.) Elenk., which consists of species 

 allied to the genus Calothrix : M.grisea Thur., M. vUiensis Asken., M. 

 robnsta Setch. et Gardn. (2) Coleospermum Kirchn., which consists of 

 species allied to Aidosira : G. Goeppertianum Kirchn., G. tenerum, G. 

 diplosiphon. (3) Leptobasis Elenk., containing L. caucasica, L. stria- 

 tula, L. tenuissima. The most marked character of this gemis is in the 

 shape of the filament, which is enlarged towards the apex and diminished 

 gradually towards the base. This singular and remarkable character is only 

 found in certain of the Scytonemaceaj. The genera Mirorhsete, Goleo- 

 spermmn and Leptobasis are obviously distributed among different sections 

 of Hormogotieaj. Microchsete, which is allied to Calothrix, goes into the 

 Rivulariea3 sub-tribe Trichophorete, although it lacks a long hair. The 

 positions of the genera Coleospermum and Leptobasis in Horraogone^e 

 is quite uncertain, and they are therefore placed provisionally in 

 Scytonemacefe. E. 8. G. 



Hormogonial Cyanophyceae of the Middle Saale Valley. — G. Schmid 

 (Bedu'igia, 1917, 58, 342-57, 1 fig. ; sec also Bot. Centralbl, 191S, 137, 

 311-2). A list of twenty-one Cyanophyce^ observed by the author in 

 Jena. The width of the filaments is considered an important systematic 

 character and is given for each species. Colour and, in many cases, 

 the direction of torsion of the filaments round their axis are regarded 

 as useful in determining species. The method of observing the torsion 

 is described. E. S. G. 



The Story of a " Water-bloom."— H. Ammann {Arch. Uydrobiol. u. 

 FlanktonJc., 1916, 11, 49G-501 ; see also Bot. Centralbl, 1918, 137, 294). 

 In the year 1907 some carp were introduced into the Wesslingsee from 

 a pond which contained Anabsena macrospora. As a result such an 

 enoiTnous mass of this alga appeared in the Wesslingsee, in which before 

 1907 no special algal growth had ever 'been observed, that the fish 

 culture was nearly ruined. The author found a dead fish of 4 lbs. 

 weight washed up on the bank which had its gills entirely glued 

 together with Anabsena. The appearance of the lake during the years 

 of water-bloom, 1908-12, is described. A marked rise in the quantity 

 of oxygen contained in the water was caused bv the Anabsena. 



E. S. G. 



Contribution to a Study of Polymorphism and of Monstrosities 

 in Desmidiacese.— F. Ducellier {Bidl S'og. bot. Ge^uve, 1915, 7, 

 73-118, 31 figs., 3 pis, ; see also Bot. Centralbl, 1918, 138, 80), The 



