458 CHARLES F. SILVESTER 



In speaking of lymph-heart formations, Dr. Huntington, in 

 his most interesting paper '^The Genetic Interpretation of the 

 Development of the Mammalian Lymphatic System,"^ makes 

 the statement that the phylogenetic history of these structures 

 permits of their presence at the posterior as well as at the anterior 

 region of the body. However, except for their presence in the 

 cervical region, as is usually the case in mammals, similar struc- 

 tures have not been recognized up to the present time in other 

 parts of the body as being carried into the adult organization as 

 portals of lymphatico-venous entry. 



The constant occurrence of communications at the posterior 

 region of the body between the lymphatic and the venous system 

 has not hitherto been shown to exist in an adult mammal. 



Huntington and McClure^ and Lewis^ have shown that the 

 permanent communications in the jugular region between the 

 jugular lymph-sac and the systemic veins appear to be formed 

 secondarily. Although a proper interpretation of the reno-caval 

 communications in South American monkeys is one which can only 

 be determined on embryological evidence, it is natural to suppose 

 that their number and position in the adult should more or less 

 conform to primary connections present in the embryo. This 

 has been shown to be the case in the anterior region of the body 

 for mammals in general in a joint paper by Professor McClure 

 and the writer.^ 



The mammalian lymphatic system as generally understood 

 is represented in B, text-fig. 2, in which only one drainage center 

 is present. The thoracic duct is situated on the right side of the 

 aorta and opens on the left side of the body at the jugular or 

 subclavian angle. 



» George S. Huntington and Charles F. W. McClure, The Anatomy and Devel- 

 opment of the Jugular Lymph Sacs in the Domestic Cat (Felis Domestica), Anat. 

 Record, vol. 2, 1908. 



' Frederick T. Lewis, The Development of the Lymphatic System in Rabbits, 

 Am. Jour, of Anat., vol. 5, 1905. 



8 Charles F. W. McClure and Charles F. Silvester, A Comparative Study of 

 the Lymphatico-Vonous Communications in Adult Mnmmals, Anat. Record, vol. 

 3, 1909. 



