Br. F. Cohn un a new genus of the family of Volvocinese. 333 



ill 1849 in his essay "Ueber einzellige Pflanzeu und Tliiere " 

 (Siebold and Kolliker^s Journal, vol. i. p. 270 ; Ann. des Sc. Nat. 

 Ser. 3. vol. xii. p. 138; Botanique, 1849). 



At the same time scarcely a single botanist has hitherto ven- 

 tured to claim as lawful property the family referred to the ve- 

 getable kingdom through Von Siebold's researches, which zoo- 

 logists are just as little inclined to give up ; and thus even in 

 the last complete enumeration of the Algae, Kiitzing's ' Species 

 Algarura ' has included only one single genus belonging to the 

 / ^olvocinece, Botryocystis, and this only in consequence of imper- 

 fect observation. Only a short time ago a most careful and 

 successful observer, to whom the study of the moving spores of 

 the Algae owes its first establishment and recently its very com- 

 plete elaboration, G. Thuret, has seen cause to conclude that the 

 Volvocinece, as well as the Euglence and even Tetraspora, are to 

 be regarded as animals, since they are destitute of the principal 

 character of all vegetable spores, germination (Ann. des Sc. Nat. 

 1850, Ser. 3. xiv. 214, 61 ; Recherches sur les Zoospores des 

 Algues et les Antheridies des Cryptogames). 



Only in the last few years has a revulsion appeared to be pre- 

 paring in this particular, since the study of the Unicellular Plants 

 has acquired a greater extension and profundity; and it is in 

 j)articular the merit of Niigeli to have investigated this hitherto 

 neglected group with a criticism and a completeness of which 

 ^ ery few other families can boast (vide his 'Neuere Algensysteme,' 

 1847, and ' Gattungen einzelligen Algen,' 1849). In consequence 

 of his researches, Nageli has ventured to include at least two of 

 the forms belonging to the Volvocinea, the genera Gonium and 

 Botryocystis, among the Algae. 



Lastly, in the past yeai', the remarkable work of Alex. Braun, 

 " Ueber die Verjungung im Pflanzenreiche,' which contains a 

 fund of the most beautiful observations explanatory of the forms 

 standing on the limits between animals and plants, has also fully 

 recognized the notions first set up by Von Siebold on this point, 

 and included the whole family of the Volvocinea in the vegetable 

 kingdom. 



I also have been led, by a series of comparative researches, to 

 the conviction, that the assignment of the character of an animal, 

 even only of the lowest Infusorium, depends merely on a one-sided 

 a'iticism of the conditions of organization ; that, on the contrary, all 

 analogy of structure and development, as well as the natural rela- 

 tionship, directly indicate to us, that the Volvocineae are to be 

 placed among plants, and indeed in the class of Algce, in these 

 again in the order of the Falmcllacece, among ivhich they form a 

 sjiecial family. 



From the contradiction which this assertion has hitherto 



