ZOOLOGY AND BOTANY, MICROSCOPYj ETC. 775 



late, and the ligtt can reach them only after heing repeatedly refracted 

 in the cells. In the pendent branches, where the leaves are better pro- 

 tected from light, the two kinds of cell lie side by side without covering 

 one another, but the hyaline cells are more tumid. Further protection 

 from the light is afforded by papillae, and the deposition of pigment in 

 the cell-walls, giving the living plant a brown appearance, especially in 

 sunny spots. 



The use of these morphological characters for purposes of classifica- 

 tion is then discussed. 



Forms of Sphagnum.* — Dr. Roll defends his previously published 

 views against the objections of Warnstorf,' and adduces additional 

 arguments in favour of classifying the numberless forms of bog-mosses 

 into a number of series passing into one another by insensible gradations, 

 rather than into sharply differentiated species and varieties. 



Algae. 



Classification of Chlorophycese.t — Dr. J. B. de Toni proposes the 

 following classification of the green algte, viz. : — 



Order I. Confer voided. 



Suborder 1. Oogamse. Families : — Coleochaetacege, Mycoideacese, 



CEdogoniacese, SphsBropleacese, Cylindrocapsaceae. 

 Suborder 2. Isogamse. Families : — Ulvaceae, Chsetophoracese, 



Ulothricacese, Cladophoracege, PithophoraceaB, Phseo- 



thamnacete, Trentepohliacese. 

 Order II. Siphone-s;. 



Suborder 1. Oogamse. Family : — Vaucheriaceae. 



Suborder 2. Anogamse. Families : — Botrydiaceae, Phyllo- 



siphonaceae, Bryopsidaceae, Derbesiaceae, Spongodiaceae, 



Udoteaceae, Valoniaceas, Caulerpaceee, Dasycladaceae. 

 Order III. Peotococcide^. 



1st Family. Volvocacese. Subfamilies : — Volvoceae (Oogameae, 



Isogameae), HEematococccEe, Cylindromonadeae. 

 2nd Family, Pahnellacese. Subfamilies : — Ccenobieae (Hydro- 



dictyeae, Pediastreae, Scenedesmeae), Pseudo-coenobieae, 



Eremobieae (Rhaphidieae, Characieae, Endosphgerieae), 



Tetrasporeae, Dictyosph^rieae, Nephrocytieae, Palmelleae. 

 Order IV. Desmidioide^. 



1st Family. Desmidiacese. Subfamilies : — Eudesmidieae, Didy- 



moideae (Closterieae, Docidieae, Micrasteriete). 

 2nd Family. Zygnemacese. Subfamilies :—Mesocarpeae5 Zyg- 



nemeae. 



Classification of Oonfervoidese.f — Prof. A. Hansgirg points out that 

 two quite different genera of algae have been confounded under the name 

 Aphanochsete, viz. : — (1) the true Aphanochsete Berth., distinguished 

 by its vegetative cells being furnished with stiff bristles, which appears 

 to be nearly allied to ColeocJisete, but differing in having no oogamous 

 mode of reproduction, and in its zoogonidia being provided with four 

 vibratile cilia instead of two ; and (2) Aphanochsete A. Br. = Herposteiron 

 Nag., belonging to the ChastophoraceEe. 



» Bot. Centralbl., xxxiv. (1888) pp. 310-i, 338-42, 374-7, 385-9, Cf, this 

 Journal, 1886, p. 108. 



t Notarisia, iii. (1888) pp. 447-53. % Flora, Ixxi, (1888) pp. 211-23, 



3 G 2 



