DEVELOPMENT OF LYMPHATICS IN ANURA tel 
of the intervening wall at the line of contact to form a teat-like 
valve. Other permanent afferent portals are formed later in a 
similar manner, there being five of these in Bufo lentiginosus 
immediately after the period of metamorphosis. 
The valve at the efferent or lymphaticovenous tap is developed 
from a circular endothelial cushion projecting into the lumen of 
the anterior vertebral vein, followed by the telescoping of this 
valvular portion of the heart deeper into the lumen of the vein. 
During the later development of the heart the efferent tap is 
shifted forward from a ventral position on the heart to an ante- 
rior one. 
While the heart is expanding, the lining cells become pro- 
gressively flattened; the mesenchymal cells external to these 
become spindle shaped and ultimately develop into muscle cells. 
Before the efferent valve has become differentiated, numerous 
blood corpuscles are found in the heart cavity. The evacuation 
of these elements doubtlessly occurs at the first vigorous con- 
tractions of the heart. 
LITERATURE CITED 
Auten, W. F. 1913 Studies on the development of the veno-lymphatics in the 
tail region of Polistotrema (Bdellostoma) stouti. First communica- 
tion: Formation of the caudal hearts. Quart. Jour. Microsc. Sci., 
vol. 59, part 2, July. 
Cuark, Exeanor L. 1915 Observations of the lymph flow and associated 
morphological changes in the early superficial lymphatics of chick 
embryos. Am. Jour. Anat., vol. 18, November. 
Fretp, H. H. 1891 The development of the pronephros and segmental duct 
in Amphibia. Bull. Museum Comp. Zool., vol. 21. 
Gaupp, E. 1899 Ecker und Wiederscheim’s Anatomie des Frosches (Zweite 
Abteilung). Braunschweig. 
Hoyer, H. 1904 Uber die Lymphherzen der Frésche. Bull. Acad. d. Sc. de 
Cracovie, Mai. 
1905 Uber das Lymphsystem der Froschlarven. Anat. Anz., Bd. 27. 
Ergiinz. Heft, 1905, und Bull. Acad. d. Se. de Cracovie, Juli, 1905. 
1908 Untersuchungen iiber das Lymphgefisssystem der Froschlarven. 
Zweiter Teil, Bull. Acad. d. Se. de Cracovie, Mai. 
Huntineton, Gro. 8. 1911 The development of the lymphatic system in rep- 
tiles. Anat. Rec., vol. 5. 
Jourpatn, L. 1883 Sur le systeme lymphatique des tetards et grenouilles. 
Comptes Rendus d. l’Acad. d. Se., T. 96. 
