MYRIAPODA. 
483 
two pairs of legs, mostly terminated by a single hook, whether these segments may be undivided 
or separated into two semi-segments, each having a pair of these organs, and of which one ! 
alone presents two spiracles.* 
The Myriapoda resemble, for the most part, small Serpents or Nereides, having the legs 
closely placed together throughout the whole length of the body. The form of these organs 
is also extended to the parts of the mouth. The mandibles are biarticulate, and immediately 
succeeded by a piece in form of a lip, divided into four parts, with the divisions articulated, or 
similar to small feet, and which, from its situation, corresponds with the tongue {languette) of 
the Crustacea : then follow two pairs of small feet, of which the second pair is in the form of 
large hooks in many, appearing to replace the four maxillae of the latter animals, or rather the 
two maxillae and lower lip of the Insects, being a kind of mouth-feet. The antennae, two in 
number, are short, and rather thickened to the tip, or nearly filiform, 7-jointed in some, much 
more numerously jointed in others, and setaceous. The eyes are generally formed of an union 
of minute ocelli; and if in some species they exhibit a facetted cornea, these facets are propor- 
tionably larger, rounder, and more distinct than in the eyes of Insects. The spiracles are 
often very small, and their number, in consequence of that of the segments, is often greater 
than in the latter, where it never exceeds eighteen or twenty. The number of these segments 
and that of the legs, increases with their age, a character which distinguishes the Myriapoda 
from the Insects, the latter being always born with the number of segments which is proper 
to them, and with all their true unguiculated feet developed at the same period, or at the time 
of their quitting the pupa state. M. Savi, jun.. Professor of Mineralogy at Pisa, has par- 
ticularly studied the luli, and observed that they are destitute, on quitting the egg, of these 
organs, so that these animals undergo a real metamorphosis. The situation of the sexual 
organs, compared with the Crustacea and Arachnida, seems to point out the separation of the 
thorax and abdomen. 
The Myriapoda live and grow longer than the other insects, and, according to M. Savi, at 
least two years are required by some (luli), before the organs of generation appear. 
From these particulars we may conclude that these animals approach the Crustacea and 
Arachnida, on one side, and the Insects on the other ; but, from the consideration of the 
presence, form, and division of the tracheae, they belong to the latter class. 
[The relations of this tribe of animals are very difficult. Whilst Latreille and Kirby regard 
them as entering the class of Insects, other authors have considered them as forming part 
of the Arachnida; and M'Leay has separated them from both these classes, and formed 
them into two orders, Chilopoda and Chilognatha, raising them, together with the two other 
orders, Thysanura and Anoplura (or Parasita, Latr.), and certain annulated Vermes, into a 
distinct class, to w^hich he applied the name of Ametahola (changeless), which Leach had 
proposed only for the spring-tailed insects and lice.] 
We divide them into two families, quite distinct, both in their organization and habits, and 
formed by Linnaeus into two generic groups. 
THE FIRST FAMILY OF THE MYRIAPODA,— 
Chilognatha, Latr. (or the genus Tulm of Linn.), — 
Has the body generally crustaceous, and often cylindrical, the antennae rather thickened at the tips, or 
nearly of equal thickness, and consisting of seven joints, two thick mandibles without palpi, very dis- 
tinctly divided into two portions by a central articulation, with the teeth imbricated and planted in a 
cavity at its upper extremity ; a kind of lip {languette, or lower lip, composed, according to Savigny, 
of the two pairs of maxillae of the Crustacea) situated immediately beneath and covering them, being of 
a crustaceous texture, flat, and divided at the outer surface, by longitudinal sections and notches, into 
* The rings of the body of insects have generally two spiracles. If 
the segments of a large Scolopendra are examined (one of those with 
twenty-one pairs of feet), it will be seen that they are alternately 
provided with, or deprived of, the two spiracles, and thus compara- 
tively they are only to be considered as demisegments. Hence each 
complete segment has tv/o pair of feet, one pair being supernumerary, 
each segment in the other insects having only a pair of feet. 
