CHAPTER XVI 



SLIME SLUGS, MYRIAPODS AND INSECTS 



Slime Slugs. The slime slugs, composing the small class 

 Onychophora of the great branch Arthropoda, are curious, soft- 

 bodied, many-legged, but sluggish creatures 

 about two inches long, that live under bark or 

 stones mostly in sub-tropic and tropic lands. 

 About fifty species of them are known. The 

 best known genus is named Peripatus. They 

 capture small insects for food by ejecting slime 

 on them from glands in the mouth. Their 

 bodies show a curious combination of worm 

 character and arthropod characters. The ani- 

 mals really seem to be a sort of link between the 

 Annelida and the Arthropoda. 



Myriapods. The class Myriapoda 1 includes 

 the familiar thousand-legged or galley worms 

 and centipedes as well as certain smaller crea- 

 tures bearing only a few pairs of legs. They 

 are land animals, and have the body segments 

 nearly uniform in size and shape, except the 

 head which bears the mouth-parts and antennae. 

 The presence of true legs on most of the seg- 

 ments of the hinder part of the body and the 

 lack of the grouping of these segments into 

 distinct thorax and abdomen are the further 

 external structural characteristics which distin- 

 guish myriapods from insects. The internal 

 anatomy corresponds in general character with 

 that of the Insecta. 



1 Modern classification tends to discard the long recognized class 

 Myriapoda in favor of two classes, one for the centipedes and allies, and 

 the other for the thousand-legged worms and allies. 



123 



FIG. 47.- 

 Peripatus el- 

 se ni (Mex- 

 ico). (Length 

 about two 

 inches.) 



