Fig. 39. Section through the olfactory involution and part of fore-brain of a larva on the ninth day after impregnation, shewing olfactory nerve.
Fig. 40. Section through the anterior part of the head of the same larva, shewing pituitary involution.
Figs. 41-43. Transverse sections through an embryo on the eleventh day after impregnation.
Fig. 41. Through fore-part of head, shewing the pituitary body still connected with the oral epithelium.
Fig. 42. Slightly further back than fig. 41, shewing the pituitary body constricted off from the oral epithelium.
Fig. 43. Slightly posterior to fig. 42, to shew 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, shewing the structure of the brain.
Fig. 45. Longitudinal section of the head of an embryo, about five weeks after hatching, 26 millims. in length, shewing the structure of the brain. In the front part of the brain the section passes slightly to one side of the median line.
Figs. 46A to 46G. Transverse sections through the brain of an embryo 25 millims. in length, about a month after hatching.
Fig. 46A. Through anterior lobes of cerebrum.