-^6 ](nHN.\L ov Comparative Nkurology. 



/•"/V-v. .)-;. Sections in the same plane t'roni older embryos of the 

 mouse. 



Fij;-. .',. Shows the relation of the olives to the roots of the trige- 

 minus, the recessus lateralis inferior being still open in part. 



F/'o-. S. Section near the tip of the cerebellum, showing the double 

 cellular layer of the dorsal surface and also the formation of the plexus 

 and cornucopia. 



Fijr. ;i. Portion of the cortex of the cerebellum in an embryo of 

 guinea-pig near the end of embryonic life. The cells of E, the super- 

 ficial proliferating layer derived from the epithelium of the recessus 

 lateralis, are frequently provided with two or more nuclei. P, zone of 

 Purkinje 'cells; N, zone of granules containing some large ganglion 

 cells; F, fibre zone with fusiform cells of the nerve sheaths. 



Fi'if. 10. Portion of the ventricular region of the same section of 

 the cerebellum with cells of the dentate nidulus. Fig. 4 of Plate II. is a 

 drawing of the entire section. 



PLATE II. 



Fi^. I. Portion of the cerebellum and medulla of the mouse embryo 

 figured upon Plate I. and lying dorsad to the section drawn in Fig. 8, 

 showing the two cellular layers, a and r, and the separating fibres, />. 



Flo-, i. Longitudinal median section of the optic lodes and cere- 

 bellum of guinea-pig embryo at an early stage. V. p., velum medullare 

 posterior; cb., cerebellum. 



Fig. 4. Longitudinal section of the cerebellum of the mouse. 



Fig. 4. Nearly median longitudinal section of the brain of a 

 guinea-pig embryo near the end of embryonic life, showing the gray 

 proliferating zone on the surface of the cerebellum (an embryonic 

 character) and the proliferating cortex. 



Fig. .5. Highly magnified cells of the deeper portions of the dorsal 

 cortex. The portion drawn lies nearly one-fifth the whole length of the 

 cerebrum from its caudad margin and nearly in the middle of the width 

 of the hemisphere. The divisions indicated in the scale have the ap- 

 proximate value of 1.25 micros. 



PLATE III. 



Sections from the brain of a young turtle. Aspidonectes spinifer. 



Figs. l-i;. Longitudinal sections passing from the lateral to the 

 median plane. I'-g-. Gasser"s ganglion; TV. :•///, ganglion of the eighth 

 nerve; P, pes pedunculi: a, frontal lobe; /', parietal lobe; c, frorrto- 

 median lobe(?); o. />./.. occipito-basal lobe (part of so-called striatum 

 or axial lobe); r./., corpus posterius; :•./>., velum medullare posterior; 

 c.c, corpus callosum; a.c, pr^ecommissura; m.c, medicommissura; ep., 

 epiphysis; gi., glomerulary zone of the olfactory lobe: cp.g.^ corpus 

 geniculatum. 



Fig. 7. Epiphysis and habena: 



