69 



I In- author 1 ) aUo made tin- liiM valuable attempts to found a 

 -Inn ot morphological description on the base ol tin- ^\ mmetry- 

 >imiplc. However he could not succeed in this, because an 



treatment of the symmetry- 

 hlem liad not yet been made, 

 at least was not known to him. 

 'ithout wishing to brittle his 

 rk, we feel compelled in the 

 it of our more modern concep- 

 to reject his system, and 

 place it by the one developed 

 iere in detail. 



It should be remarked that 

 vf course not only an organism 

 a whole, but also every part of it 

 be morphologically described 

 mains of the principles here 

 ') eloped. 



Thus the corolla of a flower 

 in have a symmetry C 6 , its calyx that of group 5, its pistil of 

 C 3 , its ovary of C 5 ; etc. 

 By simply writing 

 down the symbol of 

 its symmetry-group, as 

 adopted here, it is 

 possible to characterise 

 every form in the most 

 concise manner. 2 ) 



As instances of the 

 symmetry D^ and D%, 

 fig. 80 and 81 the crystal-forms are reproduced of chalcopyrite : 



Fig. 79- 



Acanthodesmia prismatium. 



Fig. 80. 



Cfnilcopyrite. 



Fig. 81. 

 Calotte. 



l ) E. Haeckel, Systematische Phylogenie; Entwurf eines natiirlichen Systems 

 ler Organismen auf Grund ihrer Stammesgeschichte, End. / /// Jena, (1894). 

 He speaks of four principal classes of forms: Centrostigma, Centroaxonia, Cen- 

 troplana, and Anaxonia. A comparison with our results must readily convince 

 lK)dy that in his system a confusion of all classes is present. 



-) It must be remembered here that, from a historical viewpoint, the 

 zoologist Gust. Jager had before Haeckel already made such attempts in 

 this direction, without however publishing a complete system of classification 

 based upon the symmetry-principle. 



