PROGRESS OF ZOOLOGY. 
345 
supials of Australia, and he arranged them in an order 
between the Carnassiers and Rodents, making the one great 
peculiarity in their mode of reproduction the basis of the 
order Marsupiata. This, as regards the Mammalia, was the 
distinguishing feature of Cuvier’s scheme, and it is the one 
most likely soon to undergo a complete revolution. It is 
in the classification of the tribes below the Mammalia, and 
especially the invertebrates, that Cuvier shines; as, on 
the other hand, it was amongst those that Linnaeus lost 
himself, as witness his class u Vermes,” into which he flung 
all the animals that refused to take positions among verte¬ 
brates or insects. To form a fair estimate of the progress of 
zoology in the classification of the orders in the vast stretch 
between Batrachians and Zoophytes, the &y sterna Natures must 
be explored, and its method of dealing with these compared 
with the labours of Cuvier and his successors. Still, the 
principles of classification have remained nearly the same, at 
least since Cuvier, proving how truly he seized upon the 
characteristics really indicative of structural and physiologi¬ 
cal relationships. The most important proposal for a redis¬ 
tribution is that of Professor Owen for the division of the 
Mammalia into two great groups, the designations of which 
are self-explanatory. Under Placentalia he ranges all the 
higher mammalian forms in the same order as in Cuvier's 
scheme, but the marsupiates and monotremes are separated 
to form another grand division called A-placentalia, in which 
the monotremes are ranged to correspond to the edentates in 
the first division, and as their counterparts with a less perfect 
mode of reproduction. But this, though based on obvious 
and important distinctions, appears to have found little favour 
with zoologists, and, like the labours of Grant and Blainville 
on the nervous system, is valued more for the prominence 
it gives to certain physiological facts than for its adaptability 
to the purposes of classification in the present transition state 
of zoological science. These things are, however, the proper 
fruit of the labours in philosophical zoology which have been 
conducted with such ardour in Europe during the past half 
century, and we seem now to be waiting for a second Cuvier 
who shall boldly grasp the distinctive features of the animal 
kingdom, and arrest for a time the growing tendency to trifle 
with zoological landmarks by a revision of all boundary lines, 
and fitting into their proper places all that is true and 
durable in the various systems that have been of late pro¬ 
pounded. 
The frequent varying of the basis of classification, though 
inevitable, is not the less destructive to harmony and that 
xxxvii. 23 
