Figs. 35-37. Transverse sections through an embryo on the eighth day after impregnation.

Fig. 35. Through fore-brain and optic vesicles.

Fig. 36. Through hind-brain, shewing 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 37].

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.