548 
or adult animal, but subject to important and 
very remarkable varieties ——— the progress 
of its growth. In the lower forms, such as 
Julus (fig. 304), the texture of the segments 
is hard, crustaceous, and brittle; but in the 
Scolopendroid races, the rings are flattened 
and covered above and below with tough and 
coriaceous scute, In all the Chilopoda each 
segment supports only a single pair of ambu- 
latory legs, which resemble in many respects 
those of insects, but terminate invariably in 
a simple claw. In the Chilognatha, on the 
contrary, witii the exception of a few of the 
most anterior, and likewise of the terminal 
or anal segments, each ring has two pairs 
of feet attached to its under surface, con- 
sisting apparently of two half segments con- 
joined; and this view of their composition is 
further strengthened by the fact, that a deep 
transverse indentation or groove is always visi- 
ble upon the dorsal surface, dividing the other- 
wise apparently single ring into an anterior 
and a posterior moiety, to each of which is 
fixed a pair of short and very feeble legs, com- 
posed of several distinct articulations. The 
three first segments in Julus form exceptions, 
however, to this arrangement, each of these 
supporting only a single pair of ambulatory 
feet, and these segments have been supposed 
by some authors to represent the thoracic seg- 
ments of the true insects. The seventh ring, 
likewise, in the female, has one pair deficient, 
they being replaced by the orifices leading to 
the sexual organs. The anal and penultimate 
segments are completely apodal in the Julide, 
whilst, on the contrary, in some of the Chi- 
lognatha, the size of the locomotive limbs in- 
creases progressively as we approach the caudal 
extremity, the last segment supporting the 
longest pair, which are directed backwards, so 
as to have in some measure the appearance of a 
furcate tail. 
In the Scolopendride ( Chilopoda, Latr.), a 
family which embraces those forms of Myria- 
“oaty that are most nearly allied to Insects, we 
ave a race of carnivorous Myriapods, pos- 
sessed of strong and active limbs, varying in 
number in different genera from fifteen to 
twenty-one pairs, by the aid of which they can 
run with considerable rapidity, and are able, 
owing to the flexibility of their long and 
jointed bodies, to wind their way with facility 
among the lurking places of Insects, against 
which they on an unrelenting warfare, 
All of them are found carefully to avoid the 
light, and generally to frequent damp situations, 
more especially where decaying animal or vege- 
table oo ma abound. ey lurk, therefore, 
under stones or pieces of old wood, or are met 
with beneath the bark of trees, localities which 
from their structure they are peculiarly adapted 
to occ . 
In the following account of the anatomy 
of these creatures we shall select the Scolo- 
pendre, properly so called, for particular de- 
scription, as being the largest and, conse- 
quently, most commonly met with in our 
collections, noticing, however, as we proceed, 
MYRIAPODA. 
such peculiarities as may be worthy of notice — 
in other genera. : 
The Scolopendre have their bodies com- 
posse of twenty-one segments exclusive of the — 
ead, to each of which is attached a pair of 
jointed legs. The segments are all o 
more or less quadrilateral in their s th 
transverse diameter being generally the longes 
but their size is very variable and irreg: 
The whole body is depressed, each segmer 
consisting of a dorsal and a ventral slate | 
soft but corneous consistency, formed by 
thickening of the cuticle in those regions of t 
body, while the sides to which the legs a 
appended, and where, moreover, the respirato 
spiracles are situated, are soft and of a coris 
ceous texture. ‘ 
The legs are all five-jointed and terminat 
in a simple sharp horny claw: those appends 
to the segments in the neighbourhood of t 
head are comparatively small, but as they ap 
proximate the hinder part of the body 
increase in size and strength, the last pair be 
turned backwards so as scarcely to ' 
as locomotive agents. 
The head, and more especially the ps 
entering into the construction of the oral; 
paratus of these Myriapoda, present 
difficult inquiries to the scientific entor 
who would attempt to identify them 
parently corresponding structures met witl 
the organization of the mouth of insects, < 
accordingly we are not at all surpri 
that no two authors agree as to the names | 
are most applicable to the different pieces 
longing to this portion of their economy. 1 
Myriapoda, be it remembered, are obviot 
an osculant or transition group allied 
to the Annelidans, to the Insecta, to the Ai 
nidans, and to the Crustacea. It is by 
meaus surprising, therefore, that, in the 
struction of almost every part of their bo 
we find an organization intermediate t 
these important divisions of articulated a 
as we shall again and again have occasic 
tice. But, perhaps, in no part of their eco 
is this intermediate structure better exemi 
than in the mouth of the Scolopendra, t 
different portions of which all writers ap 
to have given names rather in conformity 
their own preconceptions than with ani 
affinities that have been pointed out, o 
general view of the real nature of such 
dages. With all respect for the opinic 
preceding writers, we shall, on this ac 
endeavour, in the following deseriptio 
avoid as much as possible technicalities 
liar to the orismology of any particular 
of zoological science. ‘ 
The head of a Scolopendra, or that 
of the creature which supports the instr 
of sensation and the organs employed for 
prehension of food, appears, when ¥ 
superficially, to consist of two segments 
a circular shield-like plate, constituting tl 
head, that exists only upon the dorsal ¢ 
of the body, in which are i 
and which, moreover, coutains the eyes 
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