io8 Journal of Comparative Neurology. 



Fig. II. Sagittal mesal section of an embryo pig twenty -one millimeters 

 long. X g. 



Fig. 12, 13 and 14. Frontal sections of an embryo pig twenty-one milli- 

 meters long. Fig. 12 through choroidal fold. Fig. 13 cephalad ol choroidal 

 fold. Fig. 14 through auditory nerve, x 15. 

 PLATE VL 



Figs. 75 and 16. Reconstruction of a portion of the brain of a dog at 

 birth. In Fig. 16 the cephalic portion of the reconstruction has been removed. 

 Reconstructed from the series of sections from which Fig. 38 was taken. 9 

 diameters. 



Fig. I J. Floor of the fourth ventricle of an adult man. After Retzius. 

 X 2. 



Figs. 18, ig and 20. Reconstruction of a portion of the brain of an em- 

 bryo pig twenty-one millimeters long. Reconstructed from the series of sections 

 from which Figs. 12, 13 and 14 were taken. 17 diameters. 



PLATE VIL 



Figs. 21, 22 and 23. Frontal section of an embryo cat seventy millimeters 

 long. X 9. 



Fig. 24. Sagittal mesal section of fourth ventricle of an opossum (Didel- 

 phys virginiana). x 8. 



Fig. 25. Sagittal mesal section of the fourth ventricle of a dog at birth. 

 X 10. 



Fig. 26. Sagittal section near the meson of the fourth ventricle of a human 

 embryo of 130 days, x 5. 



PLATE VIII. 



Figs. 27, 28, 2g and 30. Transections of a human embryo of 125 days. 

 Only the brain and enough of the membranes to show the relations are drawn. 

 The sections are more advanced on the right side, x 7^. 



PLATE IX. 



^ig^- 31 1 3^1 33 and 34. Transections of the brain of a child at term. Fig. 

 31 at the calamus region, x 18. Figs. 32, 33 and 34. x 6. 



PLATE X. 



Figs, j^ and 36. Transections of the lateral recess of a child at term. Fig. 

 35, region of IX. Fig. 36, region of X. x g. 



Fig, jj. Transection of the lateral recess of a child at term, x 9. 



■^^if' 3^- Transection of the brain of a dog at birth. The section is more 

 advanced on the left side, x 8. 



