526 C. JUDSON HERRICK 



EXPLANATION OF FIGURES 



47. Transverse section through the brain of the box tortoise, Cistudo Carolina. 

 X 15. The section passes through the interventricular foramen on the left side 

 and immediately rostral to it on the right. 



48. Section through the brain of a 12.3 mm. embiyo of Chrysemys marginata 

 cut transversely to the sagittal plane and so inclined that the dorsal surface lies 

 farther caudad than the ventral. Harvard Embryological Collection, series 1087, 

 section 87. X 28. 



49. Section 96 of the same series as fig. 48. These two sections illustrate the 

 subdivisions of the diencephalon. 



50. Sagittal section through the brain of a 26.7 mm. embryo of Chrysemys mar- 

 ginata. Harvard Embryological Collection, series 1097, section 413. X 15. 



