54 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I37 

 [--- Ath 



Coel 



F2(latetal)— ^' 

 Fz(median) -' 



Fig. 4. — Embryonic development of endoderm and mesoderm. 



A, B, C, 3 stages of the development of germinal disc of Peripatopsis mosleyi 

 (adapted from Manton). D, late stage in development of coelomic sacs, Peripa- 

 topsis mosleyi (adapted from Manton). E, F, G, stages in development of meso- 

 derm and endoderm in Paraperipatus aniboinensis (adapted from Pflugfelder). 



Ant, coelomic sacs of antennal segment; Ath, anterior thickening (Manton) ; 

 Coel, coelomic cavities ; Ect, ectoderm ; Ent, entoderm ; Entzvu, point of pro- 

 liferation of entoderm (Pflugfelder) ; Fcl, coelomic sac of feeding claw segment; 

 Fs, fiber cells (Pflugfelder) ; Mes, mesoderm; Pth, posterior thickening (Man- 

 ton) ; Sip, coelomic sacs of slime papillae; Stom, stomodaeum. 



