204 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Vireti). It was collected by Viret in a depression situated between the 

 Aiguilles du Chardonnet and the Grands Mulets, at the edge of the Ar- 

 gentine glacier. The colour of the snow was dirty green, and the patch 

 extended a length of 30-40 metres, by 2-3 metres broad. In R. Vireti 

 the points of the cells are excessively long and narrow, while in R. nivale 

 Chodat the points are short. Both species are figured. The author 

 mentions also a few other algae found in coloured snow on the group 

 of Mont Blanc. 



Oxyrrhis marina.* — G. Senn has studied this organism and shows 

 that it belongs to the Dinoflagellatae, and not (as has been supposed) to 

 the Flagellatae. It multiplies by transverse division, not longitudinal 

 as is found always in the Flagellatae, aud it possesses two grooves, one 

 longitudinal the other transverse, from the bottoms of which arise the 

 two fiagella which distinguish it. One of these flagella is stretched out 

 behind while the organism is in movement, while the other causes the 

 cell to turn by means of its rapid undulatory vibrations. If it be taken 

 for granted that 0. marina has but one protoplasmic membrane it would 

 then belong to the Gymnodiniaceae, notably to Hemidinium. The re- 

 moval of this species from Flagellatae to Dinoflagellatae removes the 

 only exception to the rule that true Flagellatae multiply only by longi- 

 tudinal division. 



Fossil Algae. f — A. Bothpletz describes some fossil alga3 from the 

 Silurian beds in Gotland and Oesel. He treats of his subject under the 

 following headings :— 1 . Calcareous algse with intertwined cell-filaments. 

 Under this section three algae are described, one of which, Sphserocodium 

 gotlandic ■um, is new. 2. Under calcareous algae with cell-filaments placed 

 regularly side by side the author deals with species of Solenoporetta and 

 Solenopora, one of which, Solenopora tjotlandica, is new. The generic 

 differences between these two genera are described and the relation that 

 both hold to the Lithothamnia. After describing a new genus of Hydro- 

 zoa, containing two species, the author discusses the differences in growth, 

 both micro- and macroscopical, between the balls of Hydrozoa and those 

 composed of calcareous algae. 



Brothers Crouan.J — F. Gueguen gives a short biographical notice 

 of the brothers Crouan. Pierre-Louis Crouan was born in 1798, and 

 Hippolyte-Marie Crouan in 1802. They had a chemist's shop in Brest, 

 but retired from the business in 18G0, and thenceforward devoted them- 

 selves to the study of Botany, especially Cryptogams. The flora of 

 Finisterre was their special interest, in the study of which they explored 

 the whole region exhaustively. They collected thus an immense amount 

 of material ; and this, including the algae which had been published in 

 sets in three octavo volumes in 1852, under the title Algues marines du 

 Finistere, enabled them to write their famous Florule du Finistere. That 

 work was the crowning production of their lives, and was carefully illus- 

 trated by Hippolyte. It is a catalogue containing 1031 phanerogams, 

 20 vascular cryptogams, 247 Muscineae, 299 lichens, 2502 fungi, and 



* Arch. Sci. Phys. Nat., period 4, xxviii. (1909) pp. 492-3. 

 t K. Svensk. Vetensk. Handl., xliii. (1908) 25 pp. (6 pis.). 

 % Bull. Trimestr. Soc. Mycol. de France, xxv. (1909) pp. 69-78 (2 portraits). 



