i KI>HN\ \ni: M..J.I: .. mi BOOTfl "|;KM vs 



general shape and the cell-content* are often quite identical, there being two 

 terminal ^luhuK-s \ fat with intermediate granular protoplasm (fig. 27); a pyrenoid 

 could not ! niaili ..ut. These cells, however, differ from those of C. breviipina in 

 three prominent respects: they are always of smaller dimensions (length, 13-15 M), 

 tin v have a perfectly smooth, rather thin meniliraue devoid of spines, and the enda are 

 i ominonK more or less pointed (fig. 27) and n-\, i miiaded off to such a marked extent 

 as is the case in C. brtvispina (cf. even fig. 28 with tigs. 25, 26). Were it not for the 

 tlitlVrence of shape and the absence of all intermediate stages, these cells might be 

 regarded as young individuals of the latter ; but as it is, this view is scarcely permissible. 

 Similar though somewhat larger cells appear to have been observed by Lugerheim ' in 

 red snow from Mount iV-hindm in Ecuador; he suggests that they may belong to some 

 member of the Volvocinea-. It seems much more likely, however, that they represent 

 a species of Oocyttis. In one or two cases a considerable number (about sixteen) of 

 these cells was observed lying within a common mucilaginous investment, which would 

 point to some species like Oocystis lacustris, Chod., or O. glaocystiformi, Borge. 

 There are further resemblances to O. lacustris in the pointed shape of the cell, in the 

 (probably?) single chloroplast, and in the occurrence of oil-drops in the latter species ;* 

 also in the very feeble thickening of the ends of the cells in O. lacustris* a feature 

 which is much more pronounced in other species of the genus. For these reasons 1 am 

 inclined to regard the cells shown in figs. 27 and 28 as merely a form (f. nivalis) of 

 O. lacustris, Chod., characterised by the prominent storage of fat; 4 the cells, which 

 Lagerheim observed, may possibly belong to the same species. 



(h) SPH^ROCYSTIS SCHROETEBI, Chod., f. nivalis, n. f..(Pl. II., phot 2, S). 



In sample No. 3 of the yellow snow an organism (text fig. 1, F and 6, p. 122) was 

 very abundant, which seems to be referable to the genus Sph&rocystis of Chodat.* This 

 form consists of larger or smaller groups of round or oval cells (text fig. 1, F), green 

 in colour and with granular contents, embedded in very soft mucilage, the outline of 

 which is often irregular, but sometimes roughly circular (particularly in the case of the 

 smaller colonies). The cells arc separated by considerable intervals from one another, 

 and mostly show a very uniform distribution (text fig. 1, F); the intervening mucilage 

 is quite structureless and invisible. Each cell has a delicate bounding membrane of its 



1 Lagerheim, "Schueeflorm de* Pichincha," Btr. Dtvtxk. Bot. Get., x., 1888, p. 5*5, footnote 2 : "Zahlreiche ovale 

 Zellen,6-10p dick and 10-90 p lng, welche grtinen Intuit and an den Endenjeeinen zuweilen rothlicben (Eltropfen 

 fuhrten. Sie lagen itiinier iaoliert und konnten nicht zur Entwiekelnng gebracht warden.* 



1 Cf. Chodat, " Etodes de Biologic lacurtre," Bull. Herbitr RoMtr, v., 1897, p. 296 ; also Alyut* twrto i* la Strittt, 

 Berne, 1902, p. 190, fig. 106. 



1 Chodat'* figure* in most caie* give very little indication of thi* thickening, which wai not to be found in the 

 Antarctic specimen*. The latter may poaribly have been relatively yoong individuals, a view which ii rapported by 

 the thinnew of the wall*. See also p. 124. 



* Chodat, " Etude* de Biologic laeiutre," Bull. Hirbitr Baiuitr, v., 1897, pp. 292-295, pL ix. ; alw AlguH twto it la 

 SMUM, Berne, 1909, pp. 114, 116, fig. 63. According to O. a West (/<mrn. Linn. Soe., Bat., xixix., 1909, pp. 76, 76) 

 Sftaeroeyilu tckrotUn, Chod., and Tiinupora laeuttru. Umm., are lynonymou* (cf. alto Chodat, Alg. vtrttt, p. 1 15). 

 VOL. III. 16 



