THE LATER DEVELOPMENT OF THE FROG 133 



e. 



hftr, 



FIG. 42. Median sagittal sections through the brain of the frog. From Von 

 Kupffer (Hertwig's Handbuch, etc.). A. Of a larva of R. fusca of 7 mm. in 

 which the mouth was open. B. R. esculenta at the end of metamorphosis. 

 c, Cerebellum; ca, anterior commissure; erf, notochord; ch, habenular commissure; 

 cp, posterior commissure; cpa, anterior pallial commissure; cq, posterior corpus 

 quadrigeminum; ct, tubercular commissure; cw, optic chiasma; d, diencephalon; 

 dt, tract of IV cranial nerve; e, epiphysis; hm, cerebral hemisphere; hy, hypophysis; 

 J, infundibulum; M, mesencephalon; Ml, myelencephalon; Mt, metencephalon; 

 p, antero-dorsal extension of diencephalon; pch, choroid plexus of third ventricle; 

 R, rhombencephalon; rm, recessus mammillaris; ro, optic recess; se, roof of 

 diencephalon; t, telencephalon; tp, tuberculum posterius; tr, torus transversus 

 (telencephali) ; vc, valvula cerebelli; vi, ventriculus impar (telencephali) (third 

 ventricle). 



