13KAIN LACKING THE CALLOSUM. 



Unfortunately the membranes and plexuses had heen removed. From the precommissure (prcs.) to the 

 clotted Hue from the vrovdfornix, the narrow, white area represents the cut surface of the forntx. The 

 narrow, light area (2) extending dorso-caudad from the dotted line represents the natural margin of a ridge 

 which, had the callosum been developed, would presumably have extended across the meson and united 

 with its platetrope to form the horizontal portion of the fornix and the fornicommissure, continuous caudad, 

 through the splonium, with the callosum. In accordance with changes elsewhere indicated cs. h. represents 

 the supracomnmsure, and opticus should be preopticus ; pcs. indicates postcommissure ; i, the ragged line 

 left by tearing off the valvula. The brain was removed and hemieected by a student before the peculiarities 

 were observed and Is somewhat distorted ; the olfactory lobe (L. ol.) was partly lost, and the hypophysis 

 torn off. The medicommissure and precommissure are larger than usual. For fuller description and dis- 

 cussion see a paper ( 13) by the senior author. The specimen is 381 M. C. U. 



