438 
MESSRS. F. M. BALFOUR AND W. N. PARKER ON THE 
Figs. 35-37. Transverse sections through an embryo on the eighth day after impreg¬ 
nation. 
Fig. 35. Through fore-brain and optic vesicles. 
Fig. 36. Through hind-brain, showing closed auditory pits, &c. 
Fig. 37. Through anterior part of trunk. 
Fig. 38. Section through tail of an embryo on the ninth day after impregnation. 
PLATE 24. 
lig. 39. Section through the olfactory involution and part of fore-brain of a larva on 
the ninth day after impregnation, showing olfactory nerve. 
Fig. 40. Section through the anterior part of the head of the same larva, showing 
pituitary involution. 
Figs. 41—43. Transverse sections through an embryo on the eleventh day after 
impregnation. 
Fig. 41. Through fore-part of head, showing the pituitary body still 
connected with the oral epithelium. 
Fig. 42. Slightly further back than fig. 41, showing the pituitary body 
constricted off from the oral epithelium. 
F'ig. 43. Slightly posterior to fig. 42, to show olfactory involution, eye, 
and hyomandibular cleft. 
Fig. 44. Longitudinal section of the head of an embryo of 15 millims. in length, a few 
days after hatching, showing the structure of the brain. 
Fig. 45. Longitudinal section of the head of an embryo, about five weeks after hatch¬ 
ing, 26 millims. in length, showing the structure of the brain. In the front 
part of the brain the section passes slightly to one side of the median line. 
Figs. 46 A to 46 G. Transverse sections through the brain of an embryo 25 millims. in 
length, about a month after hatching. 
Fig. 46 A. Through anterior lobes of cerebrum. 
Fig. 46 B. Through posterior lobes of cerebrum. 
Fig. 46 C. Through thalamencephalon. 
Fig. 46 D. Through optic thalami and optic clliasma. 
Fig. 46 E. Through optic lobes and infundibulum. 
Fig. 46 F. Through optic lobes and cerebellum. 
Fig. 46 G. Through optic lobes and cerebellum, slightly behind fig. 46 F. 
