352 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
given in my preliminary paper, “The respiration of Desmognathus,” 
(Barrows, : 00). 
The question as to whether these capillaries extend into the epithe¬ 
lium of the wall was answered by sectioning a portion of the esophagus 
in this region. Examination of these sections showed the capillaries 
well within the epithelium (pi. 26, fig. 11) just as Bethge showed them 
in Spelerpes and Salamandra. 
General Conclusions. 
From these studies of the integument, from the physiological experi¬ 
ments, and from the investigations on the anatomy of the circulatory 
system, macroscopic and microscopic, we may then draw certain gen¬ 
eral conclusions:— 
Desmognathus is furnished with an important breathing organ in 
the anterior portion of the alimentary canal, mouth, pharynx, and 
esophagus. An article by H. H. Wilder (: 01 ) entitled “The pharyngo¬ 
esophageal lung of Desmognathus/’ appeared while I was completing 
my studies of the circulatory system. From the results of some of my 
work and from his own study of the respiratory muscles Dr. Wilder 
has maintained that functionally this pharyngo-esophageal region 
takes the place of a lung. 
It seems to me, however, that the skin also plays an important part 
in the respiration of this animal, as was indicated by my experimental 
tests, as well as by the extensive distribution of cutaneous blood vessels, 
and the subepidermal network of capillaries very evenly distributed 
over the entire body. The integumental region around the sides of 
the neck, where the skin is free from the underlying muscles, seemed 
to be especially richly supplied with subcutaneous blood vessels. Here 
the arteria cutanea from the pulmonary arch, and a branch of the 
arteria vertebralis collateralis, on each side, bring blood to the skin; 
while the vena cutanea parva carries the blood purified in this portion 
of the skin back to the sinus venosus, through the vena cutanea magna 
and ductus Cuvieri. 
While emphasizing, in the case of Desmognathus at least, the value 
of the function of the pharyngo-esophageal apparatus, regulated by 
breathing movements of nose and throat, I agree with Bethge in the 
importance of both anterior region of alimentary canal and skin in the 
respiration of lungless salamanders. 
