CHAPTER III 



CENTIPEDES 



Classification and distribution 



Although the Chilopoda are a widely dispersed class, the biology 

 of centipedes has attracted comparatively little attention from 

 zoologists who have tended to confine their attentions to the sys- 

 tematics of the group. In these animals, the body is divided into a 

 variable number of somites, each of which is provided with a pair 

 of limbs used for locomotion. The head bears a pair of multi- 

 segmented antennae and three pairs of mouth-parts. The first of 

 these post-oral appendages are toothed mandibles, the second are 

 foliaceous maxillae, while the third are leg-like palps. Behind the 

 head is the first segment of the body, known as the basilar seg- 

 ment. Its appendages are the maxillipedes or taxocognaths. These 

 are poison-claws with which the prey is captured and killed. At the 

 tips of their strong, piercing terminal segments are the orifices of 

 the ducts of the paired venom-glands. Where present, the eyes are 

 in the form of clusters of ocelli, except in the Scutigeromorpha 

 which have compound eyes (see below). The number of legs 

 varies from fifteen to over a hundred pairs, but however many 

 there may be, the number is always odd. Each somite of the body 

 is flattened when seen in cross-section and is composed externally 

 of a dorsal plate or tergite and a ventral sternite united by pleural 

 membranes with which the legs articulate and upon which the 

 spiracles leading into the trachea usually open. 



The class Chilopoda is sub-divided into five orders. The first of 

 these, the Geophilomorpha, includes the long, worm-like centi- 

 pedes with the pairs of legs varying in number from 31 to 177. 

 The fore part of each somite is marked oflp from the hinder part by 

 a distinct joint, there is a pair of spiracles on each segment except 

 the first and last, and the antennae are always composed of four- 



40 



