Phylum Arthropoda 491 



the sides of the mouth are two jaws, while the roof of the anterior portion 

 forms a muscular ridge armed with small chitinous teeth. On either 

 side of the mouth are the oral papillae which are assumed to be sensory. 

 The genital opening is between the last pair of legs, and the anus 

 opens at the end of the body. Sexes are separate. The male has paired 

 testes and ciliated ducts. The female has paired ovaries and oviducts, 

 portions of which are specialized as uteri. The spermatazoa are de- 

 posited as spermatophores on the female's body. The sperm make their 

 way to the oviducts where fertilization apparently takes place. Develop- 

 ment of the eggs occurs inside the oviducts by means of a placental-like 

 attachment. It appears that the 30 or 40 young are born after a year's 

 time. 



Fig. 160. The onychophoran, Peripatus. A, Lateral view of entire animal; 



B, ventral view of anterior end. 



These unusual animals live chiefly in moist places such as under 

 logs and in leaf mold, where they feed on small insects. These are cap- 

 tured by means of their heavy jaws, and the animals seemingly protect 

 themselves by means of their ability to eject a sticky slime from slime 

 glands which open on the oral papillae. 



The arthropod characters possessed by this group are the hemo- 

 coel, dorsal heart, the reduced coelom, chitinous exoskeleton, respira- 

 tion by tracheae, and the jaws. The annelid characters are the seg- 



