which | 
“.4 derive from the knowledge of these changes sufficient information to 
“. assign a definite position to all the subordinate groups in each of these 
% 
‘ie, 
124 Scientific Intelligence. 
pupa of insects, and in which the joints of the abdomen alone remain 
movable, is also the case among the highest Crustacea. The position 
‘ of the insects as the highest class, can no longer be denied, when we 
consider that in them the body is at last divided into three distinct 
regions—head, chest and abdomen—and that the locomotive append- 
ages, which, in the lower classes, are so numerous and uniform along 
the whole length of the body, are reduced to the region of the chest, 
and assume there a particular development. 
_ Again, the transformation of the respiratory organs is an additional 
evidence in favor of such an arrangement, as will be admitted from the 
fact that Worms and Crustacea have chiefly a branchial respiration, 
while in insects it becomes aérial, at least in their perfect condition. 
Oneé-upon this track, it was easy to follow out the minor changes 
h these animals undergo during their final transformation, and to 
classes. Taking the insects, for instance, into special consideration, 
we ascertain readily that chewing insects rank below the sucking tribes, A 
as their larvee are chewing worms, provided with powerful jaws, even ; 
in the case of those which, like Lepidoptera, have the most perfectly 
deyeloped sucking apparatus in their mature condition. 
_ Again 
their formation, and the manner in which they are unfolded, when the 
inasmuch as the upper larval wings of Lepidoptera are a sort of elytra, 
which, afier being cast in the last moulting, are succeeded by the more 
perfect membranous wing, which in its turn, undergoes such a develop- 
ment as to assign to those Lepidoptera, which have their wings folded ma 
backwards and enclosing the body, a position below those in which the 
wings spread sideways; and the highest position to those which raise 
their wings upwards. So that these investigations have settled even 
at in other classes ; as, for instance, among Meduse, where naked-eyed 
Discophori, with alternate generations, must be considered as the lowest 
type, recalling, in one of their conditions, the appearance of the inferior ‘ 
class of polypi ; when the covered-eyed Discophori, with their strobiloid = 
generation, begins in its lowest state with a medusoid polyp. : 
Similar facts are known among Echinoderms, in which, among Cri- 
noids, the highest free forms begin with germs provided with a stem, 
thus assigning, on embryological grounds, a lower position to all those 
a 
which are provided with a stem 2 
__ In the same manner has it been possible to determine the position 
Bryozoa among Mollusca below Ascidize, upon the ground that their 
embryonic development is similar. It has been possible, in the sam 
way to assign to Pte a @ position inferior to that of Ga | 
proper, and not intermediate between Gasteropoda and Cep 
