Cervical Veins and Lymphatics in Human Embryos. 



37 



onic stages to the adult. Thus in man, according to Sebileau and 

 Demoulin/^ "Faraboeuf has well shown that the facial vein, lingual 

 vein, and superior thyreoid vein unite to form a common canal very 

 happily termed the thyreo-linguo^facial venous trunk. This arrange- 

 ment is in fact very frequent." Except for the superior thyreoid 

 vein, which has not yet developed, this description may be applied 

 to the embryonic vessels shown in Fig. 2. 



Y card.post. 



Fig. 3. From a human embryo of IG.O mm. (H. E. C, 1322). x 20 diam. 

 V. ceph., Vena cepbalica. For other abbreviations see Fig. 1. 



The study of the veins in the embryos just described led to the 

 following observations upon the lymphatic vessels. In the 10 mm. 

 embryo (Fig. 1), the jugular sac is represented by a single lymph 

 space in close relation with the anterior cardinal vein. It appears to 

 be lined with endothelium, which in some sections has shrunken away 

 from the surrounding mesenchyma. It contains a few blood corpus- 



"Sebileaii. P., and Demoulin, A. Comment il faut cbmprendre le systeme 

 des veines jugulaires ant^rieures. Bull, de la soc. anat. de Paris, 1892, annee 

 67, pp. 120-132. 



