MYRIAPODA. 247 



in their organization and habits, and forming two genera ac- 

 cording to the system of Linnseus. 



FAMILY I. 



CHILOGNATHA(l). 



The body generally crustaceous and frequently cylindrical; 

 the antennae somewhat thicker near the end or nearly equal, 

 and composed of seven joints ; two thick mandibles without 

 palpi, very distinctly divided into two portions by a median 

 articulation with imbricated teeth, implanted in a cavity of its 

 superior extremity; a species of lip ligula(2) situated im- 

 mediately above, that covers them, is crustaceous, plane, 

 and divided on its exterior surface by longitudinal sutures 

 and emarginations into four principal areas, tuberculated on 

 their superior margin, the two intermediate of which, nar- 

 rower and shorter, are placed at the superior extremity of 

 another area, serving as a common base : the feet very short, 

 and always terminated by a single hook ; four feet, situated 

 immediately under the preceding part, of the form of the 

 following ones, but more closely approximated at base, with 

 the radical joint proportionably longer; most of the others 

 attached in double pairs to a single annulus. The male or- 

 gans of generation are situated immediately after the seventh 

 pair of feet, and those of the female behind the second. The 

 stigmata are placed alternately, outside of the origin of each 

 pair of feet, and are very small. 



The Chilognatha move very slowly, or slide along, as it 

 were, and roll themselves spirally or into a ball. The first 

 segment of the body, and in some the following one, is the 

 largest, and has the form of a corselet or little shield. It is 

 only at the fourth, in some, and at the fifth or sixth in others, 

 that the duplication of the feet commences; the first two or 



(1 ) Chilognatha, Lat. or the genus Iuirs, Lin. 



(2) The lower lip composed of the two pairs of jaws of the Crustacea, accord- 

 ing to Savigny. 



