128 JOHN LEWIS BREMER 



cardial cavity, but prevented from crossing the median line by 

 the presence of the median pharyngeal outgrowth to form the 

 trachea, extends to the lungs as the pulmonary arteries, which 

 are later joined by vessels springing from the dorsal aortae. 

 These vessels, which may be double and plexiform, constitute 

 the fifth (and sixth) arch. 



Although dealing in this paper with the development as found 

 in rabbit embryos, I have examined various other species, as 

 chick, pig, sheep, etc., and feel satisfied that in all essential points 

 the story of the development of these primary vessels in other 

 vertebrates will be found similar to that here described. 



LITERATURE CITED 



Bremer, John L. 1902 On the origin of the pulmonary arteries in mammals. 

 Am. Jour. Anat., vol. 1, p. 137, and Anat. Rec, vol. 3, p. 334. 



Evans, H. M. 1909 In Keibel-Mall Entwickelungsgeschichte, vol. 2, p. 551, 

 etc. Anat. Rec, vol. 3, p. 498. 



Fedorow, V. 1910 Ueber die Entwickelung der Lungenvene. Anat. Hefte. 

 Bd. 40, S. 529. 



His, W. 1900 Lecithoblast und Angioblast der Wirbelthiere. Abh. d. math.- 

 phys. Klasse d. Kgl. Sachs. Ges. d. Wiss. Bd. 26, no. 4. Leipzig. 



RtJCKERT u. Mollier 1906 Die Entstehung der Gefasse und des Blutes bei 

 Wirbelthieren. Handb. d. vergl. u. expt. Entw. d. Wirbelthiere, her- 

 ausg. von O. Hertwig. Bd. 1, S. 1019. 



Turstig, J. 1884 Untersuchungen iiber die Entwickelung der primitiven Aorten. 

 Schrift., herausg. v. d. Naturf.-Ges. bei. d. Univ. Dorpat. Bd. 1. 



