Arteries in Monsters of the Dicephalus Group 453 



solely upon its outer lingual artery for nourishment. After giving oif 

 the single dorsal branch which strikes into the interior of the head, the 

 median compound external carotid continues forward through the S- 

 shaped interstice and emerges upon the face as already described. At the 

 first curve of the S it gives off two lateral branches, one turning to the 

 right to course over the inner lateral and dorsal surfaces of the face of 

 component A, the other turning to the left to a like distribution over 

 component B. 



The subsequent course of their lesser branches is strikingly identical. 

 Each gives off near its origin a delicate branch which may be a pharyn- 

 geal {?), and just beyond a very short artery which almost immediately 

 bifurcates into two terminal branches that break up in the muscles at 

 the angle of the mouth. These branches are obviously superior and in- 

 ferior labials, therefore their stem is a very much shortened facial, which 

 is quite in keeping with the anatomical condition, for the shortness of the 

 inner mandibles brings the ramus and the angle of the jaw in a perpen- 

 dicular line to the angle of the mouth. Immediately beyond the facial 

 a long slender artery passes dorsally and caudally over the roof of the 

 cranium and loses itself in the tissues around the outer periphery of the 

 median eye. These terminal twigs had not taken the injection mass, 

 and it was difficult to trace them thus far, but there is no question in my 

 mind but that the artery which gives them origin is a superficial temporal. 

 Near its beginning this vessel gives off an insignificant branch which 

 ramifies the tissues at random over the median dorsal region anterior to 

 the median eye. This may be an anterior auricular which has no legiti- 

 mate distribution, owing to the fact that there is no median ear to call 

 it into normal physiological service. Beyond the root of the superficial 

 temporal an attenuated branch from the external carotid mounts to the 

 dorsal surface of the snout and tmites with one of the two branches 

 which ramify this region and terminate in a single stem issuing from a 

 foramen. The position of this foramen together with the fact that from 

 it also issue a few nerve fibers establish it as a greatly reduced infraorbital 

 foramen. A similar foramen, exhibiting identical relationships, is also 

 present upon the inner side of the other component. Obviously, then, 

 the blood-vessel is an infraorbital artery with its terminal branches, and 

 the attenuated communicating branch is merely an anastomosing branch 

 from the facial. 



Having given off the two lateral branches, whose lesser branches have 

 just been followed over the face, the main artery continues its serpentine 



