3 1 2 CRITIQ UES ~AND A DIGRESSES. -J [x 1 1 . 



Birds, and of the highest forms of Reptiles, should have 

 been crowded into the time during which the Permian 

 conditions quietly passed away, and the Triassic condi- 

 tions began ? Does not any such supposition become in 

 the highest degree improbable, when, in the terrestrial or 

 fresh-water Labyrinthodonts, which lived on the land of 

 the Carboniferous epoch, as well as on that of the Trias, 

 we have evidence that one form of terrestrial life per- 

 sisted, throughout all these ages, with no important modi- 

 fication ? For my part, having regard to the small amount 

 of modification (except in the way of extinction) which 

 the Crocodilian, Lacertilian, and Chelonian Reptilia 

 have undergone, from the older Mesozoic times to the 

 present day> I cannot but put the existence of the 

 common stock from which they sprang far back in the 

 Palaeozoic epoch ; and I should apply a similar argu- 

 mentation to all other groups of animals. 



IV. Professor Haeckel proposes a number of modifica- 

 tions in Taxonomy, all of which are well worthy of con- 

 sideration. Thus he establishes a third primary division 

 of the living world, distinct from both animals and 

 plants, under the name of the Protista, to include the 

 Myxomycetes, the Diatomacece, and the Labyrinthulce, 

 which are commonly regarded as plants, with the Noc- 

 tilucce, the Flagellata, the Rliizopoda. the Protoplasta, 

 and the Monera, which are most generally included 

 within the animal world. A like attempt has been 

 made, by other writers, to escape the inconvenience of 

 calling these dubious organisms by the name of plant or 

 animal ; but I confess, it appears to me, that the incon- 

 venience which is eluded in one direction, by this step, 

 is met in two others. Professor Haeckel himself doubts 

 whether the Fungi ought not to be removed into his 

 Protista. If they are not, indeed, the Myxomycetes 

 render the drawing of every line of demarcation between 



