ON THE CETONIID/E OP SOUTH AFRICA. 
7 
which serves in some degree to insulate it from other groupes. But it is evident that we 
must previously have arrived at the knowledge of the groupe ; and this is effected by a close 
watching of the variation of affinity, and by considering the groupe to be complete only when 
the series of natural objects returns into itself. It is more particularly when we have satisfac- 
torily applied this test of the groupe’s completeness, that we ought to look out for its natural 
character. Still, after all, we may be wrong ; we may sometimes imagine a groupe to return 
into itself, when it does not ; or we may consider what in reality are two groupes, to form 
only one. The best way I know of correcting such evils, is to recollect that the natural 
system ought to express all the relations which exist between the various objects of our 
study, and that if any of these are left unrepresented in our arrangement, there must be 
some latent error, in the formation of our groupes. I repeat, that the process is one of 
tatonnement. The marsupial animals have clearly some kind of relation to Primates, to 
Insectivorous Per a, to Edentata, and also to G lives. Now, if a naturalist cannot express all 
these relations, and at the same time all the various relations which exist among the other 
groupes of Mammalia, he ought to be convinced that his arrangement is wrong. It is of 
no use to talk about the importance of this organ, or of that other, in the structure of 
these animals. If even we were right in any such comparative estimate of the importance of 
organs in general economy, we ought not to forget that the true question under consideration 
is, the natural arrangement of the animals themselves ; and that this is to be attained only 
by the expression of every affinity, and every analogy that can be detected. The unnatural 
groupe Pestacea, was founded on the important character of the presence of a shell ; and we 
shall see among the Cetoniidee, that genera were erroneously separated from this family 
because they wanted its leading characters, which consist in the membranaceous texture of 
certain parts of the mouth. 
I have before alluded to the fact, that when a series of affinity is followed, it is observed 
to return into itself, and thus to form a closed groupe. Now, if we start from the principle 
that when a few species first agree in some particular character, they combine into a series 
that will return into itself, we shall probably imagine every such series, so forming a circle 
in practice, to be in theory the first natural assemblage of species. Yet this will be an 
incorrect mode of viewing the matter ; for owing to the rarity of its species, the first known 
circular grouping of the species of Cryptodinus, for instance, is into sub-genera; whereas 
the first known circular grouping of the species of Cetoniidce is into certain sub-sections. 
But, if the above hypothesis were true, the sub-genera of one genus would be equivalent 
in value to only sub-sections of the other. I conceive, therefore, that in order to attain 
accuracy in the distinction of groupes, we must proceed in a totally different manner to 
investigate the subject. In the first place, we must commence from some given point in 
which all naturalists agree, touch a point undoubtedly is the animal kingdom. Every one 
acknowledges this groupe. Now I observe the animal kingdom to resolve itself into five 
natural groupes, forming a circle. I observe again, each of these circular groupes to resolve 
itself into five others, and so down, until I arrive at species. Now it is clear that I may 
term the animal kingdom a genus, or I may call the groupe Vertebrata a sub-genus, and 
Mammalia a kingdom ; the word given as a name to the class of groupe, being adopted 
for convenience, and being merely conventional. My aim is not to dispute about the 
propriety of the names given to these various groupes, but merely to express the proper 
subordination of one groupe to another, even supposing that they had no names. If, therefore, 
