PLATE LXXV. 



Fir,. 178. Similar preparation at the thirty-sixth hour. a. Upjier layer. 6. Parietal lamella, lainhm /<'//- 

 tralit (limit, n\ukvli>l<itte). c. Lamina teroia, visceral lamella (ltiir>nf<isfr)ilittt>-). <(. Lower layer. /. Central 

 nervous system. g. Chorda dortalis. h. Proto-vertebne. i. Wollfiau body. k. Pleuro-peritoneal fissure, b, c, 

 k, i, y, are products of differentiation of the middle layer, p. 156. 



Flf:. 179. Section of area opaca, and a portion of arta pelJucida of blastoderm (caudal end), at the thirtieth 



hour. A)', .\ri-n /ifllurit/,!. .In. .\r,-n <,/,<icit. I,. \'\t\ H -r, c under. M middle layer of germ. <. Liinihui >,,- 

 trails, d. Lamina serosa. /. Blood-vessels. </. Klemunta which belong tu tbo middle layer, and particularly to 

 the lamina scrota, h. Yolk of the Inner yolk riiu. 



FK;. iffy. Transverse section through the cervical part of an embryo of tin- rliiek at the thirtieth hour of 

 incubation, u T : in'r layer of the germ. b. Central nervous syutom. r. <-i,,,,;i,i ,/..,.,//,. ,/. i'i-,.t,, , 

 e. Lamina wntralix. /. Lamina terosa. g. Lower layer. 



