CHAPTER XIV 



PHYLUM ARTHROPODA (continued) 



Classes (continued) ONYCHOPHORA or PROTOTRACHEATA ; 

 MYRIOPODA; and INSECTA 



THESE three classes form a series of which winged insects 

 are the climax. The type Peripatus is archaic, and links 

 the series to the Annelids : the Myriopods lead on to the 

 primitive wingless insects. All breathe by tracheae tubes 

 which carry air to the organs of the body and all have 

 antennae; hence they are often united under the title 

 Tracheata Antennata. 



First Class of Tracheata Antennata. ONYCHOPHORA or 

 PROTOTRACHEATA 



GENERAL CHARACTERS 



The body is worm-like in form, soft-skinned, and without 

 external segmentation. 



The appendages are a pair of prominent pre-oral antenna, 

 a pair of jaws in the mouth, a pair of slime-secreting oral 

 papilla, which development shows to be true appendages, 

 numerous pairs of short, imperfectly jointed legs, each with 

 two claws, and a pair of anal papilla, which are rudi- 

 mentary appendages. The legs contain peculiar (crural) 

 glands. 



Respiration is effected by numerous unbranched trachea 

 with openings irregularly scattered. The heart is an elongated 

 dorsal vessel with valvular ostia. There is a series of 

 nephridia in the legs. The halves of the ventral nerve-cord 

 are widely separate. All are viviparous. 



