CLASSIFICATION. 35 



a class, the Monera or Homogenea, regarded by him 

 as occupying a lower plane in the evolution or differ- 

 entiation of structure. Others, notably Biitschli, con- 

 sidered a merely negative distinction valueless, and 

 subsequent investigation has confirmed their judgment. 

 The presence of nuclei or nuclear substance, in some 

 form, has been demonstrated in many species where 

 formerly it was not suspected. Assuming Biitschli's 

 dictum to be well grounded, that " the nucleus needs 

 the plasm and the plasm the nucleus," in the develop- 

 ment of a perfect organism that the activities of 

 both are reciprocal, and one without the other cannot 

 live, a conclusion strongly deducible from all that has 

 been ascertained regarding their vital functions 

 Haeckel's separation of the apparently non-nucleated 

 forms from the general group seems unwarranted, 

 and his term " Monera," and also " Homogenea," 

 should disappear. 



Professor Lankester describes the substitution, in 

 his genus Archerina, of a chlorophyl-coloured capsule 

 for the nucleus proper, it is representative, in fact, of 

 the nucleus, and whilst refraining from the assertion 

 that no existing Protozoa are devoid of nucleus, corre- 

 sponding in this character with the non-nucleated 

 Protophyta (e. g. Bacteria), he found the inclusion, in 

 his proposed system of classification, of the Homo- 

 genea, impracticable, and chose to defer taking that 

 step until it had been conclusively shown that forms 

 now regarded by some as homogeneous (Biomyxa, 

 Gymnoplirys, etc.) are really so. The general relations 

 of these apparently non-nucleated forms with the 

 nucleated most nearly allied to them cannot be ignored 

 in any systematic arrangement. And, it may be 

 added, in any case the form of the nucleus, when 

 present, is of little specific value. 



The arrangement here adopted is, in its main 

 features, on the lines now most generally accepted by 

 Continental authors, whose long-sustained and fruitful 

 investigations entitle them to respect. 



