THE PHARYNGO-CESOPHAGEAL LUNG OF 
DESMOGNATHUS. 
HARRIS H. WILDER. 
SINCE the discovery of lungless salamanders in 1894, numer- 
ous investigators have endeavored to ascertain the method of 
respiration in these forms. Camerano (1894), after a series of 
physiological experiments upon Sfelerpes fuscus, came to the 
conclusion that integumental respiration was no better devel- 
oped than in other Amphibia, and that the respiration must 
be mainly bucco-pharyngeal. Directly along this line Maurer 
(1897) showed that in lungless forms the pharyngeal capillaries 
pass beyond the corium and actually invade the epidermis, a 
condition unique among vertebrates. Hopkins (1896) supplied 
an interesting point of negative evidence, that in lungless sala- 
manders the pulmonary vein is entirely wanting, and that cor- 
respondingly the left atrium is reduced to a rudiment. This 
view was slightly modified by Bruner (1900), who showed that 
what Hopkins had taken for the septum atriorum was really a 
valve and that a proper septum did not exist, hence the single 
atrium of lungless forms is probably due to a confluence of the 
original two. 
A careful study of the blood vessels of both lunged and 
lungless salamanders was conducted by Bethge (1897), with 
the result that he located in the latter (Spelerpes fuscus) a 
pharyngeal plexus of capillaries, the vessels of which seemed 
swollen at irregular intervals. Miss Woldt (1897) found a 
pulmonary artery in Plethodon, supplying both cesophagus 
and skin. 
Thus far, however, the investigation seems to have centered 
about the organs of circulation, and, consequently, a curious 
set of facts along a different line has been entirely overlooked. 
Although these have been met with and described by various 
investigators, no conclusions have been drawn from them. 
183 . 
