MIDBRAIN AND THALAMUS OF NECTURUS 



347 



bushy and thorny dendrite is directed ventrally into the veiy dense neuropil 

 of this nucleus, vvhich occupies a ventro-medial position and is traversed by the 

 slender varicose longitudinal axons, some of which come from the tractus haben- 

 ulo-peduncularis and which descend through this neuropil far into the medulla 

 oblongata. The axon of this neuron is not impregnated, but other preparations 

 show that axons of this nucleus descend in the longitudinal tract shown. X 74 

 (cic, 2-2-2) 



Fig. 62 Median section through the diencephalon and mesencephalon, re- 

 constructed from sagittal sections by the Weigert method (series ciii). The 

 sections from which the drawing was made are slightly oblique to the sagittal 

 plane, which was, accordingly, reconstructed by the superposition of camera 

 outlines of the necessary sections made on tracing paper. Comparison with 

 gross preparations cut in the sagittal plane confirms the relations. X 13. 



Fig. 63 Drawing of a graphic reconstruction of the median section of the 

 brain. This was made on the basis of the same series of sagittal sections used 

 for figure 62, as described on page 227. The details of the ventricular sculpturing 

 were controlled by comparison with gross preparations cut in the median plane, 

 and the drawing is a composite, including some slight modifications derived from 

 the gross preparations as studied under the stereo-binocular microscope. X !?• 



Fig. 64 Key drawing to accompan\' figure 63. X 13. 



