664 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Hydrurus.* — J. Eostafinski giyes the following diagnosis of this 

 little-known genus of algae, which forms brown slimy flocculent 

 masses in cold rapidly flowing water : — " Thallus hydrobius, lubricus, 

 disco conico affixus, elongatus, usque ad tres decimetros longus, ex 

 uno podio principali, in medio latissimo, ramos laterales emittens ; 

 inferne simplex, plerumque nudus, primo intuitu gelatinosus, in tactu 

 duriusculus sed elasticus, solidus aut rarissime senilitate canescens ; 

 semipellucidus, ochraceus; superne aut simplex aut penicillatus, 

 varioque modo divisus ; semper tota sua superficie, ramulos minores 

 filamentis tenuissimis obtectos, ex olivaceo fuscos aut nigros pro- 

 ducens." 



The peculiar mode of reproduction takes place only by night. The 

 lower branches of the thallus begin to swell, and the gelatinous 

 matrix of the cell- walls deliquesces and at length altogether disappears. 

 The brown endochrome, previously in the form of bands or caps, 

 collects into globular bodies which at length pass into a tetrahedral 

 form, furnished with projecting ridges or beaks. These develope 

 directly into a new thallus. 



The nearest ally of Hydrurus is Woronin's genus Cliromophyton,-\ 

 which does not necessarily inhabit the leaves of Sphagnum. The two 

 genera agree in their gelatinous deliquescent cell-walls ; but the 

 reproductive bodies of Chromophyton have more the character of 

 zoospores. Eostafinski proposes to unitethem into a new family under 

 the name Syngeneticae. 



Relationship of Palmella to the Confervacese.J — Colonies of 

 Palmella uvceformis Ktz., gathered by J. B. Schnetzler in a small 

 stream near Lausanne, were found to be composed of minute cells, 

 about • 01 mm. in diam., congregated into a gelatinous mass. Placed 

 in spring water, and covered with a watch-glass, they produced 

 zoospores, which swam about with great activity, and finally formed a 

 green coating on the sides of the glass. After a time they germinated, 

 and developed into a green alga composed of branched filaments of 

 elongated cylindrical cells with lateral excrescences. Similar filaments 

 also developed directly from the gelatinous cells of the Palmella. On 

 evaporating, the cells separated from one another, assumed a globular 

 form, and transformed themselves back again into gelatinous colonies 

 of Palmella. The filaments thus produced were a Stigeoclonium, or 

 some nearly allied confervaceous alga. The water-bed in which the 

 Palmella was originally found was sometimes full of stagnant or 

 running water, sometimes completely dry ; at that time the alga was 

 accompanied by quantities of diatoms and by crystals of calcium 

 carbonate. 



These observations complete others previously made by Cienkowski 

 and Famintzin on the disintegration of Stigeoclonium and of another 

 confervaceous alga into Protococcus-cells, which have led Kutzing and 



* Eostafinski, J., ' Hydrurus u. seine Verwandsckaft.' 34 pp. (1 pi.) Krakow, 

 1 882 



f See this Journal, i. (1881) p. 100. 



% Bull. Soc. Vaud. Sci Nat., xviii. (18S2) pp. 115-6. 



