PLATE Х. 
Entire Embryos of Cynthia partita; Gastrula to Tadpole. 
Muscle cells shaded by vertical lines, mesenchyme by transverse lines, nerve plate and tube by fine 
stipples, chorda by coarse stipples. 
Figs. 148-151.—Four views of the same embryo; fig. 148 dorsal, 149 ventral-posterior, 150 same view 
but deeper level, showing mesoderm and endoderm, 151 right side. Many of the ecto- 
derm cells are passing into the 10th generation. 
Figs. 152-154.— Three views of one embryo ; fig. 152 dorsal, showing closure of the blastopore from in 
front, 153 same view but deeper Tva, showing cells beneath the ectoderm, 154 ventral 
view of mesoderm and endoderm below ectoderm. 3 
Figs. 155 and 156.—T wo ventral views of an advanced gastrula, the first showing the superficial ecto- 
derm, the latter the endoderm and mesoderm lying beneath the ectoderm. 
Fig. 157.— Left side of embryo, showing, in optical section, muscle cells, mesenchyme, chorda and nerve 
plate 
Figs. 158 and 159. rwn optieal sections of the same embryo, the former (158) through the open blas- 
topore at the posterior end of the ететі the latter (159) through the region anterior to 
the bla astopore. 
Figs. 160-162.—Three views of the same embryo from the ventral side but drawn at different levels; 
160 surface view showing ectoderm ; 161 same view deeper level, showing mesoderm and 
endoderm ; 162 same view still deeper level, showing chorda, mesoderm and endoderm. 
Fig. 163.—Dorsal view of embryo of same stage as preceding showing nerve plate and tube, mesoderm 
and chorda. 
Figs. 164 and 165.—Two views of same embryo from right side; fig. 164 median optical section show- 
ing chorda, nerve tube and endoderm; 165 more superficial view showing muscle cells 
and mesenchyme. 
Fig. 166. _Older embryo from right side, showing in optical section nerve iube; chorda, mesoderm and 
endoderm. 
Fig. 167.— Young tadpole from left side showing in optical section nerve tube, chorda and mesoderm. 
