382 Introduction to Animal Morphology. 



mouth prolonged into a sucking tube ; the body covers the 

 limbs ; surface smooth (Polyzonium), or rough, and 70-, 80- 

 jointed (Siphonophora). 



Order 2. Chilopoda {Latreille) — somites flattened, each 

 with a dorsal and ventral plate, and not more than one pair 

 of limbs ; antennae of more than fourteen joints ; generative 

 organs posterior. The third thoracic ring has a free dorsal 

 plate; so has the second in Lithobius and Geophilus; penis 

 none ; stigmata lateral ; the first and second pair of legs con- 

 verted into foot-jaws, the hinder of which is perforated by the 

 poison-duct, and claw-like ; the stigma pairs are fewer than 

 the somites. The larvae may have 6-8 pair of legs, and new 

 segments arise between each pair of their predecessors. The 

 mandibles are weak, with rudimental palps. The last pair of 

 legs are often turned directly backwards. There are two 

 families, i. Cermatiidae — antennae bristle-like, longer than 

 the body ; limbs long, especially the last pair ; those of the 

 first thoracic ring palp-like, with no end claw ; stigmata in 

 the middle line of the back, ex. Scutigera. 2. Scolopendridae 

 — antenna subulate, shorter than the body ; eyes never com- 

 pound ; stigmata lateral. The antennae are polyarthrous, 

 bristle-shaped in Lithobius, or fourteen- (Geophilus), seven- 

 teen- (Cryptops), nineteen- (Eucory^bas), or 18-, 20-jointed 

 (Scolopendra) ; the ocelli are usually four, and the body seg- 

 ments unequal (Scolopendra, &c.), or equal, as in the blind 

 Cryptops and Geophilus. Heterostoma has large, sieve-like 

 stigmata. Arthronomalus electricus is phosphorescent. 



Order 3. Pauropoda {Lubbock) — minute (to" long), white, 

 with no tracheae ; ten somites sparsely setose ; generative 

 organs anterior; legs nine pairs, of which one is on the third, 

 and two pair on each of the fourth, fifth, sixth, and seventh 

 segments. The head has no foot jaws ; the antennas are five- 

 jointed, bifid, with three long, many-jointed appendages ; the 

 larva is hexapodal ; dorsal plates, like those of Chilopoda. 

 This includes one genus. Found in decaying leaves in tem- 

 perate climates. 



