202 



OXYCHOPHORA. 



places with the lateral spaces, so that, where this is the case, the 

 nephridia and the longitudinal nerves come to lie in one common 

 cavity. 



Several cavities unite to form the central space which, in the 

 adult, contains the intestine and the genital organs. According to 



Fig 101. — Transverse sections through embryos of P. capensis at different ages, A being taken 

 through the segment of the oral papillae (somewhat diagrammatic, after Sedgwick), d, 

 intestine; Ih, dorsal and ventral median portions of the body-cavity; m.lh, lateral portion 

 of the median body-cavity; n, rudiment of the ventral cord; tie, nephridia (in A, rudi- 

 ment of the salivary glands) ; oe, external aperture of the same ; p, limb ; pe, pericardial 

 cavity ; p.lh, pedal body-cavity ; sh, segmental cavity ; us, dorsal portion of the primitive 

 segments ; vo, ventral organs. 



Sedgwick, two new spaces (Fig. 101 B, pe and m.lh) appear on the 

 outer side of each of the dorsal portions of the primitive segments 

 (sh), the wall of which to some extent forms their inner boundary. 



