920 
ME,. A. FRASER 0N THE DEVELOPMENT OF THE 
Forty Figures in all: Of these there are 11 in Pig embryoes, 6 in the Human embryo, 
3 in the Sheep, 2 in the Hog, and 18 in the Eat. 
PLATE 54. 
Figs. 1-3. Sections through Pig embryoes 1 centim. in length X 25. 
Fig. 1. Longitudinal vertical section, showing gasserian ganglion, 
maxillary and mandibular branches of the fifth, the latter 
dividing into two; the seventh nerve, with its mandibular 
(chorda tympani) branch joining the inner of the two branches 
of the mandibular division of the fifth. 
Fig. 2. Longitudinal vertical section, showing auditory vesicle, ganglion 
acusticum, dorsal aorta with the origin of the arteria stape- 
dialis. Both figures have been cut along the obliquity of the 
arches. 
Fig. 3. Transverse vertical section, showing the auditory vesicle, primitive- 
jugular vein, facial nerve, and dorsal aortse ; the section is very 
oblique, shows on one side the open cleft. 
Figs. 4-7. Section's through Pig embryoes 1*4 centim. in length X 25. 
In the first three figures the sections are made along the obliquity of the 
arches. In all the figures a large number of consecutive sections have been 
used to fill in the outlines of the cartilages and periotic capsule. 
Fig. 4. Longitudinal vertical section, showing eye, nose, mouth, cartilages 
of mandibular and hyoidean arches, mandibular branch of the 
fifth, with its outer and inner divisions, facial nerve with its 
mandibular (chorda tympani) branch, and meatus auditorius 
externus. 
Fig. 5. Longitudinal vertical section much the same as preceding, but 
hyoidean cartilage continuous throughout its entire length, 
short crus of incus commencing to be formed, although too 
strongly indicated in the diagram. 
Fig. 6. Longitudinal vertical section, showing gasserian ganglion, ganglion 
of olfactory nerve giving off two sets of branches, standing over 
nose cleft, ganglion and trunk of facial; stapes and stapedial 
artery, primitive jugular vein, periotic capsule and semi-circular 
canals, and junction of hyoidean cartilage with cartilage of first 
branchial arch (thyro-hyoid). 
Fig. 7. Transverse vertical section, showing incus, hyoidean cartilage, 
stapes, and stapedial artery, periotic capsule, basis cranii, 
