241 



to the rostral end and meets the nervous wall between the lateral lobes 

 in front (Fig. 4). In the lower wall at the rostral end is found a 

 large decussation (Figs. 3—6) which probably represents the pallial 



^^■'.■/I'.K/.y tr. pc] ].r. 



Fig. 25. 



commissure of selachians. It seems probable that the primordium 

 hippocampi which occupies the massive roof in selachians has been 

 drawn forward in Chimaera until it extends into the rostral and rostro- 



Fig. 26. 



ventral wall. If so, the behavior of the tractus pallii is fully ex- 

 plained. 



A further indication that the above interpretation is correct is 

 found in the relations of the posterior pallial commissure. From the 

 region of the primordium hippocampi a strand of gray matter con- 



Anat. Anz. XXXVI. Aufsätze. 16 



