452 Mabel Bishop 



the anterior cornu it gives off a large branch which distributes itself 

 in the tongue of component B after the manner of a normal lingual 

 artery, for such it is unquestionably. This lingual -sends off a smaller 

 but conspicuous branch to the symphysis menti, which branch enters 

 the mandible through a foramen on its inner lateral side close to the 

 symphysis. These foramina, one on each inner lateral side of the sym- 

 physis, are quite large and conspicuous in young pigs. A bristle passed 

 through one of them emerged from the most anterior of the mental 

 foramina. In three specimens examined a definite branch from the 

 lingual passed into each of these foramina, yet I failed to find them 

 named in any of the literature, or given particular mention. There- 

 fore, in order to designate the conspicuous branch that passes into them, 

 I shall refer to them as the sub-symphysial foramina. Both the lingual 

 and the sub-symphysial branch give off many small twigs to the mus- 

 cles of the tongue. About a centimeter farther forward the main artery 

 gives rise to a pair of lateral branches ; one, another lingual with its sub- 

 symphysial branch to supply the inner side of the tongue of component 

 B, the other suggests the corresponding artery to the inner side of the 

 tongue of component A, of which only the sub-symphysial branch has 

 been preserved. The hypothetical former condition is represented in the 

 plate by a dashed line (x'). The parent artery sends off from its dorsal 

 wall many small collateral branches in pairs, which supply the inner 

 lateral borders of the two tongues. Immediately anterior to these a 

 single branch is given off, which proceeds dorsally in the median plane 

 and passes into the interior of the head just posterior to the angle of 

 the united mandibles. This could not be followed beyond this point 

 without spoiling the specimen for further investigation. In the Plate 

 it is deflected to one side in order to render it visible. The distribution 

 of the branches of the main artery thus far establishes it as a Median 

 Compound External Carotid, fulfilling a normal function for com- 

 ponent B and in addition partially supplying component A. The only 

 striking deviation from the normal distribution in component B is that 

 both Unguals arise from the same external carotid, instead of one lingual 

 from each. The remainder of the ventral surface of component A 

 is supplied by collateral vessels from the right common and external 

 carotids as would be expected normally. Note, however, that there is a 

 reduction in the tongue supply. It is nourished by only one lingual 

 artery, which has a normal origin but does not give off a sub-symphysial 

 branch. It will thus be seen that the tongue of component A depends 



