The alligator and its allies . sverse diameter is greater than their longi-tudinal. The tapering, cephalic end of each hemi-sphere forms an olfactory tract, I, which extendsccphalad to form the olfactory bulb, B. ol. Lyingbetween the caudal ends of the hemispheres is asmall conical body, , called by Bronn andothers the pineal body. The writer has found (62),however, that this body is the paraphysis ratherthan the epiphysis. Caudad to the ccrebra-hemispheres and in contact with them are theoptic lobes, MH; they have about the sameshape and position as in the frog, but are muchsmaller in pro
The alligator and its allies . sverse diameter is greater than their longi-tudinal. The tapering, cephalic end of each hemi-sphere forms an olfactory tract, I, which extendsccphalad to form the olfactory bulb, B. ol. Lyingbetween the caudal ends of the hemispheres is asmall conical body, , called by Bronn andothers the pineal body. The writer has found (62),however, that this body is the paraphysis ratherthan the epiphysis. Caudad to the ccrebra-hemispheres and in contact with them are theoptic lobes, MH; they have about the sameshape and position as in the frog, but are muchsmaller in proportion to the size of the caudad to the optic lobes is the cere-bellum, HH, somewhat elliptical in outline as seenfrom above. Extending caudad from beneath the cerebellumis the medulla, NH, with its triangular fourthventricle. The outlines of the medulla are some-what obscured by the numerous roots of theeighth to eleventh cranial nerves, VIII-XI, whicharise along its dorsal border. The medulla, as was. JuJ tfir I n V Hyp Fig. 30. Brain of Alligator. (A, dorsal; B, ventral; andC, lateral view.) (From Wiedersheim, slightly altered.) VII, cerebral hemispheres, each of which gives rise postero-laterally to ahippocampal lobe partially overlying the corresponding optic tract,; ZII, thalamencephalon; Mil, optic lobes; ////, cerebellum;NH, medulla oblongata; I-XII, cranial nerves; I, 2, first and secondspinal nerves; !, olfactory bulb; Tro, olfactory tract; , para-physis; Jnf, infundibulum; Hyp, hypophysis; Med, spinal cord. The Nervous System 133 said above, passes, as is usually the case, withoutany line of demarcation into the spinal cord, theobex filling in the apex of the fourth ventricle at theanterior end of the median dorsal fissure. A lateral view of the brain is shown in Figure30, C. The hemisphere, VH, is conical in outline,with a small projection from the posteroventralregion; its continuation forwards as the olfactorytract, Tro., and b
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