36 Frederic T. Lewis. 



was reported subsequently.^ They are present in an embryo of 9I/2 

 days (3 mm.). Usually the linguo-facial vein arises from the anterior 

 cardinal near its outlet, but sometimes it connects with the common 

 cardinal vein (duct of Cuvier) and in one exceptional case — the left 

 side only of an embryo of 12 days (5 mm.) — it emptied into the 

 posterior cardinal vein. In a 7 mm. rabbit the median lingual por- 

 tion of the vein has been seen to bifurcate symmetrically, agreeing 

 with Grosser's description for the bat. In rabbits from 9.5 to 29 

 mm. the main trunk of this vein has been shown in a series of six 

 reconstructions.^'^ Its terminal branches are the anterior and pos- 

 terior facial veins, the latter receiving a posterior auricular branch; 

 thus it corresponds with the external jugular vein of the adult rabbit 

 as described by Krause, and it has been so labeled. This vein, how- 

 ever, seems to be homologous with the common facial vein in man, 

 the external jugular vein of human anatomy arising independently 

 as will be seen presently. 



In a recent publication Grosser has shown that the linguo- 

 facial vein is homologous with the inferior jugular vein of fishes, 

 amphibia, and reptiles, — a paired ventral vessel draining the floor of 

 the branchial region. ^^ In the same paper he states that this vein is 

 well developed in cat and guinea-pig embryos and in a human embryo 

 of 6.5 mm. Grosser's comparative studies demonstrate the funda- 

 mental importance of this vein. The name inferior jugular has, 

 however, not been adopted in this paper since it is an unfortunate 

 desigiiation for a ventral vessel in fishes, which has nothing to do 

 wdth the anterior (t. e., ventral) jugular vein of man, but gives rise 

 to veins which empty anterior or superior to the other jug-ulars. The 

 term linguo-facial is justified by the embryonic distribution of the 

 vessel, — in part to the lingual region (hyoid and mandibular arches) 

 and in part to the superficial tissues of the mandibular region. 

 Although there is a complex rearrangement and new formation of 

 branches, a single large vein drains this territory from early embry- 



•Lewis, F. T. The intraembryonic vessels of rabbits from Sy^ to 13 days. 

 Proc. Amer. Assoc, of Anat., 1903, pp. 12-13. 



"Lewis, F. T. The development of the lymphatic system in rabbits. Amer. 

 Journ. of Anat, 1905, Vol. 5, pp. 95-111. 



"Grosser, O. Die Elemente des Kopfvenensystems der Wirbeltiere. Verb. d. 

 anat. Gesellschaft, 1907, pp. 179-192. F. R. Lillie refers to this vein in the 

 chick as the external jugular. Development of the Chick, Chicago, 1908. 



