MR. W. K. PARKER ON THE STRUCTURE AND 
. 4. Horizontal section below the cranial cavity, exposing first arch, notochord, and 
investing mass. X 10 diameters. 
A subhorizontal section through the eyes and root of tongue. Xx 10 diameters. 
5. 
. 6. Part of the head, with outer part of cheek pared away. x 12 diameters. 
ls 
A section made through the plane of the hinder part of cranium. x 12 dia- 
meters. 
8. Part of same section. x 20 diameters. 
. 9. A similar section. * 26 diameters. 
10. Another subhorizontal section through the top of the first postoral cleft. x 20 
diameters. 
PLATE XXX. 
Second Stage-—Lmbryo Pig, 1 inch long. 
. |. Section across the end of the snout. x 10 diameters. 
. 2. Section through ethmoid region, root of tongue, and larynx. xX 12 diameters. 
g. 8. Section nearly in plane of the notochordal region, front view. x 10 diameters. 
. 4, A similar section, lower down. x 10 diameters. 
i 
g. 5. Part of a similar section through apex of mandibular arch, front view. x 15 
diameters. 
. 6. A similar section through apex of next arch, front view. x 15 diameters. 
g. 7. Another similar section through periotic capsule in plane of horizontal canal. 
x 10 diameters. 
Third Stage—Embryo Pig, 1% inch long. ; 
. 8. Part of a section through top of second postoral arch, corresponding with fig. 6 
of second stage, front view. x 15 diameters. 
g. 9. Side view of the three postoral arches. x 15 diameters. 
PLATE XXXT. 
Third Stage (continued). 
1. Ist section through nasal region. x 7} diameters. 
. 2. 2nd section of same. x 74 diameters. 
ig. 2%. Part of fig. 2. x 223 diameters. 
2 
g. 3. drd section of same. x 74 diameters. 
27) 
. 3, Part of same section. x 224 diameters. 
. 4. 4th section of same. x 74 diameters. 
. 5. Oth section of same. x 74 diameters. 
.. 6. 6th section of same. x 74 diameters. 
6*. Part of fig. 6. x 20 diameters. 
7. Tth section of nasal region. »x 74 diameters. 
Va 
. Mandibular portion of same section. x 73 diameters. 
