CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF 
THE MUSEUM OF COMPARATIVE ZOÖLOGY AT HAR- 
VARD COLLEGE. E. L. MARK, Director. No. 167. 
A CASE OF ABNORMAL VENOUS SYSTEM IN 
NECTURUS MACULATUS. 
THEODORE H. ROMEISER. 
Ix all classes of-vertebrates variations in the morphology of 
the circulatory system are by no means infrequent. Indeed, one 
rarely, if ever, finds two individuals with precisely the same 
arrangement of the blood.vessels. Even in cases in which the 
vessels are for the most part symmetrical, the smaller vessels, 
particularly the veins, are found to vary more or less on opposite 
sides of the body, as is readily shown by a comparison of the 
superficial veins of one's own forearms Or the backs of the 
hands. 
The literature on abnormalities of the blood-vessels shows that 
they often may involve even the largest and most important 
veins of the body, such as the postcava and its tributaries. It 
has been observed that in the venous system of some verte- 
brates the cases of variation are more frequent than those of 
the “normal” condition. Thus McClure (:004) finds variations 
in the opossum of such frequent occurrence and of so definite a 
character as to suggest probable phylogenetic relations. 
The literature on abnormalities of the veins in Urodela shows 
records of several cases, mostly in European salamanders. 
Hochstetter ('88, p. 164) describes a condition in Salamandra 
maculosa in which the postcava did not pass through the liver, 
but was continuous with the much enlarged right posterior car- 
dinal vein, the two forming a single vessel passing straight to the 
venous sinus. He also briefly mentions similar abnormalities 
seen in specimens of Szredon pisciformis. ue 
Joseph (:01) observed in Salamandra maculosa à similar case, 
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