DEVELOPMENT OF GERMINAL LAYERS IN MAMMALS. 453 
Fic. 7.—Oblique section of another ovum from the same uterus as that 
represented in Fig. 6. x 566. 
Fie. 8.—Oblique section of the ovum of a mouse at the seventh day. 
x 566. 
Fie. 9.—Mesial longitudinal section [slightly oblique] of another mouse 
ovum at the seventh day. x 566. 
Fig. 10.—Slightly oblique longitudinal section [eighth of fourteen] of a 
mouse ovum about the middle of the seventh day. x 566. 
Fic. 11.—Longitudinal section of the ovum of a mouse [eighth of seven- 
teen] at about the end of the seventh or in the early part of the eighth 
day. xX 566. 
Fie. 12.—Longitudinal section of the ovum of a rat [seventh of thir- 
teen] at a period corresponding to the end of the seventh or the early par 
of the eighth day in the mouse. x 566. 
Fig. 13.—Mesial longitudinal section of an ovum of a rat at a period 
corresponding to the second half of the eighth day in the mouse. xX 89. 
Fig. 13.4.—Mesial longitudinal section of the central portion of the 
embryonic area of a rat’s ovum from the same uterus as the ovum repre- 
sented in Fig. 13. x 283. 
Fie. 13 B.—Mesial longitudinal sections of the anterior and posterior 
ends of the embryonic area of an ovum from the same uterus as that 
represented in Fig. 13. x 283. 
PLATE XXIV— 
Fics. 13 C—G.—Transverse sections of the germinal area of a rat’s ovum 
from the same uterus as the ovum represented in Fig. 13. The positions 
of the sections are indicated by the lines ¢, d, e, f, and g respectively in 
Fig. 13. x 283. 
Fic. 14.—Slightly oblique longitudinal section [sixteenth of thirty] of an 
ovum of a rat at a period corresponding to the eighth day in the mouse. 
x 85. 
Fic. 14.4.—Mesial longitudinal section of the central portion of the 
germinal area of a rat’s ovum from the same uterus as the ovum represented 
in Fig. 14. x 283. 
Fies. 14.8 and C—Transverse sections [slightly oblique] of the germinal 
area of a rat’s ovum, taken from the same uterus as the ovum represented 
in Fig. 14. The positions of the sections are indicated by the lines 4 and 
ec respectively in Fig. 14a. x 283. 
Fies. 14 D—F.—Transverse sections [slightly oblique] of the germinal area 
of a rat’s ovum, taken from the same uterus as the ovum represented in 
Fig. 14. The positions of the sections are indicated by the lines d— 
respectively in Fig. 14. x 283. 
Fic. 15.—Mesial longitudinal section of the embryonic area of a mouse 
ovum at the ninth day. x 150. 
VOL. XXXIII, PART III.—NEW SER. HH 
