MYRIAPODA. 483 



two pairs of legs, mostly terminated by a single hook, wliethcr these segments may be undivided 

 or separated into two semi-segments, each having a pair of these organs, and of whicli one 

 alone presents two spiracles.* 



The i\Iyriapoda resemble, for the most part, small Serpents or Nereides, having the legs 

 ch)sely 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 biartieulate, and immediately 

 succeeded by a ])iece in form of a lip, divided into four parts, with tlie divisions articulated, or 

 similar to small feet, and which, from its situation, corresponds with the tongue (langiwtte) of 

 the Ci-ustacea : 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 maxillic of the latter animals, or rather the 

 two ma.\illa; and lower lij) of the Insects, being a kmd of mouth-feet. The antenna, two in 

 numljcr, are short, and rather thiekeued to the tip, or nearly filiform, /-jointed in some, nuich 

 more numerously jointed in others, and setaceous. The eyes are generally formed of an union 

 of minute oceUi; 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 numlier 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 unguiculatcd 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 Arachuida, seems to ]ioint out the separation of the 

 thorax and abdomen. 



The Jlyriapoda live and grow longer than the other insects, and, according to M. Savi, at 

 least two years are required by some (lull), 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 tracliete, they belong to the latter class. 



[The relations of this tribe of animals are very difficult. Whilst Latreille and Kirby regard 

 tlu'm as entering the class of Insects, other authors have considered them as forming part 

 of the Arachnida; and iM'Leay has separated them from both these classes, and formed 

 them into two orders, Chilopoda and Chiloynatha, raising them, together with the two other 

 orders, Tlnjsanura and Anoplnra (or ParasUa, Latr.), and certain annulated Vermes, into a 

 distinct class, to which 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 bv Liuulcus into two generic groups. 



THE FIRST r.lMILY OF THE MYRIAPODA,— 

 Chilognatha, Latr. (or the genus lulus of Linn.), — • 

 Has the body gencrahy crustaceous, and often cylindrical, the antennic rattier thickened at the tips, or 

 ncaiiv of equal thickness, and consisting of seven joints, two thick mandibles without palpi, very dis- 

 tinctlv divided into two portions by a central articulation, with the teeth imbricated and planted in a 

 cavitv at its upper extremity ; a kind of lip {lanijuetie, 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 crustaccous texture, flat, and divided at the outer surface, by longitudinal sections and notches, into 



* The rin^rs of tlie body of iiisccts tiine gciicr^illy two sjjiraLk. 

 S aesiioL-iits of Fi liLTge Scolopeiidra iirL- txaniiiiud [one of tliost 

 "nIv-oriL' pairs of ffet), it will be seen tliiit they are (ilten 

 miied ivitli, or deprived of, tlie two spiraeies, and thus enii 



tively they are only to be considered as demisepinents, Heiiee each 

 complete segoietit has two pair ot feet, one pair beini,' supeniutnerary, 

 each segment in the other insects having only a pair of feet. 



