CLAY POLE, 
iS) 
\O 
oa) 
EXPLANATION OF PLATE XXIV. 
Development of the Reproductive Cells. 
Fic. 49. Transection showing early mesoderm formation. Letters as before. 
Borax carmine. Obj. 7, oc. 2, tube length 15}. 
Fic. 50. Transection through somite on one side of body in embryo of age 
shown in Fig. 44, 2d abd. segment. guc., germcells. Delafield’s haematoxylin. 
Obj. 75, oc. 6, tube length 15}. 
Fic. 51. A similar section of same age as in Fig. 50. me.s., mesoblastic so- 
mite, cavity distinct. Borax carmine. Obj. +44, oc. 6, tube length 153. 
Fic. 52. Longitudinal section through under part of abdomen of later embryo. 
mc., beginning of muscles; other letters as before. Delafield’s haematoxylin. 
Obj. #5, oc. 4, tube length 153. 
Fic. 53. Longisection through abdomen of stage shown in Fig. 45. sp.me., 
splanchnic layer of mesoderm; 4@/.c., blood corpuscles ; other letters as above. 
Delafield’s hematoxylin. Obj. +4, oc. 4, tube length 15}. 
Fic. 54. Longisection through hinder part of abdomen of embryo in corre- 
sponding stage (slightly oblique). @z., anus; rest of letters as before. Germ 
cells are migrating intothe yolk. Delafield’s haematoxylin. Obj. #5, oc. 4, tube 
length 153. 
Fic. 55. Longisection through embryo. me., two layers of mesoderm, splanch- 
nic and somatic. Delafield’s haematoxylin. Obj. ;4;, oc. 6, tube length 15}. 
Fic. 56. Similar section to Fig. 55. s.g.c., stationary germ cells; m.g.c., 
migrating germ cells. Delafield’s haematoxylin. Obj. 5, oc. 6, tube length 15}. 
Fic. 57- Section showing migrated germ cells and scattered degenerating 
yolk nuclei, y.c. Obj. #;, oc. 4, tube length 15}- 
