178 George 8S. Huntington and Charles F. W. McClure. 
ContTents—Continued 
5. Fully developed veno-lymphaticstage...................:tee- veces 277 
6:. Pre-lymphatie staize ic: a ite wee Sater tern ooh cites ced hat Oe eee 288 
7. Lymphatic stage or stage of definitely organized jugular lymph sac. . 297 
LV General considerations and conclusions... 05.222. a ene ree 307 
Explanation of -firuresw sss. sek de nee ee ae ee ee ee 308 
INTRODUCTION. 
In January, 1908, the writers read a paper before the Associa- 
tion of American Anatomists upon the ‘‘Anatomy and Develop- 
ment of the Jugular Lymph Saes in the Domestic Cat.’’ This 
paper, which includes merely an outline of the development 
of the sacs was subsequently published in the Proceedings of the 
Association.’ 
In dealing with this subject in the present paper 1% 1s the inten- 
tion of the writers to give a minute and detailed account of the 
development of these sacs in the domestic cat so that every phase 
and condition of their development may be represented and illus- 
trated by a series of reconstructions, which are as accurately repro- 
duced as their complicated character will permit. The object of 
presenting so detailed an account is, to place beyond the range of 
inference all doubt that has hitherto existed regarding the venous 
origin of the jugular lymph saes, as well as to establish a basis 
for the study of the development of this portion of the lymphatic 
system in other mammalian embryos.’ 
In a more recent article on the “Cervical Veins and Lymphatics 
in Four Human Embryos” (Am. Jour. of Anat., vol. 9, page 38), 
Dr. Lewis states as follows concerning the first appearance of 
lymphatics in human embryos: 
No lymphatics could be found in a 9.2 mm. embryo, so that the jugu- 
lar lymphatics probably arise in human embryos of about 10 mm. This , 
‘Huntington and McClure: The Anatomy and Development of the Jugular 
Lymph Saes in the Domestic Cat. The Anatomical Record, vol. 2, nos. 1 and 2, 
1908 (pages 1-18, 17 figs.). 
*In a paper by N. W. Ingalls (The Anatomical Record, vol. 2, no. 8, 1908), 
dealing with the vascular system of a 4.5 mm. human embryo, certain vessels are 
figured which open into the post and precardinal veins near their confluence to 
form the duct of Cuvier. These are undoubtedly, as Ingalls suggests, veno- 
lymphatic anlages of the jugular lymph sae, if judged by the corresponding 
structures observed in embryos of the cat. 
—— 
