APPENDIX D. Ixxxi 



showed that the protoplasm of the spores of Botrytis infestans 

 (the potatoe mould) is at times differentiated, and ultimately 

 resolved into active flagelliferous Zoospores, quite undistin- 

 guishable from certain infusoria, have met their parallel in a 

 memoir lately published by MM. Famintzin and Boranetzky 1 , 

 respecting a similar differentiation in the gonidia of lichens 

 belonging to the genera Physcia and Cladonia. It is, however, 

 only certain of the gonidia which are so circumstanced ; the 

 contents of others simply divide into motionless globules.' 



Phytozoa. Concerning the organisms belonging to this 

 class Dr. Arlidge writes 2 : 'The remarkable phases of 

 existence through which any one species may pass upsets all 

 our notions based on presumed constant characters : for, as 

 we have seen, one and the same being may at one period of 

 its existence exhibit in a preponderating degree the vital 

 phenomena of an animal, at another those of a plant, whence 

 has arisen the hypothesis of the metamorphosis of plants 

 into animals, and vice-versa! In another place 3 he says : 

 ' In point of fact these organisms stand on the confines be- 

 tween the animal and the vegetable kingdoms, some genera 

 distinctly belonging to the latter, others doubtfully to the 

 former, whilst many pass through such phases of existence 

 that at one time they assume the characters of animals, at 

 another those of plants.' 



Cohn's experiments 4 on Stephanosph&ra are very valuable, 

 because they show the direct influence of external conditions 

 in modifying the characters of such organisms. We will 

 quote Dr. Arlidge's account of these experiments. He 

 says: 'On placing specimens of this organism, some in 



1 Translation in ' Ann. and Mag of Nat. Hist.,' Feb.. 1869. 

 a Pritchard's ' Infusoria,' p. 1 28. 3 Loc. tit. p. 



' Nov. Act. Acad. Curios.,' xxvi. 1857. 

 VOL. II. f 



