Hyatt.] 50 [March 5, 



different branches of the same common stock as parallelisms. 

 The history of modern classification is mainly a series of rectifi- 

 cations of the mistakes made by the older naturalists in associat- 

 ing animals of the same stock but of different genetic groups, 

 because they were misled by these purely representative and 

 genetically disconnected parallelisms. The separation of the 

 branch of the Articulata into numerous types, and the new classi- 

 fications of the Crustacea, the association of the Fishes and Ba- 

 trachians in one type and of Reptiles and Birds in another, are 

 good illustrations of this remark, as well as the researches of 

 Wurtemburger and the author upon fossil Cephalopoda, Cope 

 upon Batrachians and Reptiles, Marsh and Gaudry upon Mam- 

 malia. There is we think just as much evidence for the view 

 that the Metazoa sprang by gradations yet to be discovered from 

 the compound colonial amoeboid Protozoa, as there is that they 

 came directly from colonial forms of the Flagellata or Ciliata. 

 Butschli's late discoveries seem to be turning the scale in favor 

 of the latter hypothesis, but, even these are still insufficient to 

 fill the gap between the Metazoa and the Flagellata. 



In the Biologisches Centralblatt, March 1884, vol. iv, no. 1, p. 

 5, he points out among the Flagellata, that Eudorina has male 

 and female colonies of zoons. The male colony gives birth by 

 self-division to a second series of colonies, which eventually unite 

 with the female zoons of the female colonies and fecundate them. 

 These secondary colonies of male zoons, be calls on account of 

 their peculiar forms and offices, the " Spermatozoonplatten der 

 Eudorina." In Volvox globator separate sexual colonies are not 

 produced, but in this well-known globular form with its numer- 

 ous flagellate zoons, certain of these become differentiated into 

 males, and others into females. The male zoons become, through 

 successive divisions, reduced to Spermatozoonplatten like those 

 of Eudorina and these then conjugate with and fertilize the 

 female zoons. In this form we are, therefore, thanks to Butschli, 

 made acquainted with a true colony, consisting of a number of 

 associated zoons, which has arisen like tissue in the egg by divis- 

 ion from one cell, and in which also, as in Metazoa, cells or zoons 

 become differentiated into males and females. This comparison 

 is also still farther carried out by the fact, that the males 

 undergo, as do spermatocysts, spontaneous division and thus pro- 



