844 RECORD OF CURRENT RESEARCHES RELATING TO 



stones in streams at Vallombrosa, near Florence. Looked at from the 

 surface, tlic autheridia-beariug tliallus appears to be covered by a 

 number of roundish or irregular, somewhat elevated, pale dots, con- 

 sisting of a number of densely-crowded antheridia. They are elon- 

 gated cylindrical cells, developed vertically from the apex of the 

 superficial cells of the thallus, twenty or more from a single cell. 

 Their contents are at first homogeneous, but are subsequently differ- 

 entiated into seven or more nearly globular antherozoids, placed in a 

 row one above another, which are set free by the rupture of the mother- 

 cell. 



New Vaucheria * — M. Woroniu describes, under the name 

 V, de Baryana, a new Vaucheria collected by him in streams near 

 Montreux, on the Lake of Geneva, but also earlier by De Bary and 

 Peyritsch near Halle. 



The thallus scarcely differs in any respect from that of other 

 species of the genus. The filaments are more or less branched, usually 

 from 0'03 to 0*04 mm. in diameter; the chlorophyll is fine-grained, 

 and of a bright green colour. Notwithstanding this, the tufts of tbis 

 alga have a very pale green or even a grey tint, owing to their being 

 copiously encrusted, when old, with calcium carbonate, to such an 

 extent that on the death of the filament the encrustation frequently 

 remains behind in the form of a connected tube. Tbis is not an 

 encrustation from without, but a secretion from the substance of the 

 Vaucheria itself. 



From the thallus spring the fertile branches, erect lateral sboots, 

 0'2-0*3 mm. in length, containing a great quantity of oil and chloro- 

 phyll. The extremity of each of these branches develops gradually 

 into an antheridium. While this is taking place, a lateral protuber- 

 ance is formed on the upper balf of the branch, which becomes a 

 stalked oogonium. The development of the two organs advances 

 pari passu, so that ultimately tbeir orifices stand on the same level. 

 The terminal antheridium and stalked oogonium determine V. de 

 Baryana to belong to Walz's section, Vaucherice racemosce, but it differs 

 from the other species in the form of the antheridium. Instead of 

 being curved, with the form of a horn or hook, it has two blunt 

 lateral projections, whicb give it the appearance of tbe handle of a 

 crutch ; the projections are, bowever, sometimes three or four in 

 number. The form of the antheridium bears the nearest resemblance 

 to those in V. piloholoides and sphierospora ; but these species belong 

 to a different section. The orifice from whicb the antherozoids escape 

 is always at the end of these protuberances. The oogonia are spherical 

 and stalked. 



The process of fertilization takes place in the same way as in 

 other species of the genus. The mature oospore is usually quite 

 spherical, and fills up the whole of the oogonium ; occasionally it is 

 beaked. 



Normally there is a single superior antheridium, and a stalked 

 oogonium ; occasionally two antheridia accompany a single oogonium, 



* ' Bot. Zeit.,' xxxviii. (1880) p. 425. 



