CHAPTER XVII. 



TRACHEATA. 



PROTOTEACH EAT A . 

 THE remarkable researches of Moseley (No. 396) on Peripatus 



FIG. 167. ADULT EXAMPLE OF PERIPATUS CAPENSIS, natural size. (From Moseley.) 



capensis have brought clearly to light the affinities of this form with 

 the tracheate Arthropoda; and its numerous primitive characters, such 



FIG. 168. Two STAGES IN THE DEVELOPMENT OF PEEIPATUS CAPENSIS. (After 

 Moseley.) 



A. Youngest stage hitherto observed before the appearance of the legs. 



B. Later stage after the legs and antennae have become developed. 

 Both figures represent the larva as it appears within the egg. 



1 and 2. First and second post-oral appendages. 



as the generally distributed tracheal apertures, the imperfectly seg- 

 mented limbs, the diverging ventral nerve cords with imperfectly 



