516 'Journal of Comparative Neurology and Psychology. 



Fig. 8. No. 1926. Diagram of the cerebral arteries viewed from above, as they He at the base of 

 the skull. The cavernous portions of the carotid arteries are exposed, and the dotted line shows the 

 position of the anomalous carotid branch. 



Fig. 9. No. 1926. Diagram of the arrangement of the arteries of the base of the brain in Case 1926, 

 viewed from below as they lie on the brain. The point of origin of the anomalous branch and its junction 

 with the basilar artery are shown. 



Fig. 10. Case 1909. Thrombotic softening of the left hemicerebrum from a thrombus, situated in 

 the intracranial portion of the left carotid artery; the anterior communicating artery and the posterior 

 cerebral artery of the same side being small, partly obstructed by arterio-sclerosis, and insufficient to 

 maintain the circulation. Thrombosis of the right carotid would not have so resulted on account of the 

 large size of the posterior cerebral and the normal size of the posterior communicating artery. 



Fig. II. Case 1954. Set of cerebral arteries showing almost all of the common anomalies, with 

 their compensatory relationships. I, The anterior communicating is large and modified by enlargement 

 of the left anterior cerebral; 2, left anterior cerebral large, right small; 3, both posterior communicating 

 large, corresponding post cerebral arteries small, especially the right; 4, left superior cerebellar artery 

 double; 5, right vertebral artery small, and the posterior inferior cerebellar receives nearly all of the 

 blood brought by the vertebral; 6, left vertebral artery as large as the basilar. An aneurism on the 

 right middle cerebral artery at the origin of its principal branches. 



