830 The American Naturalist. [October, 
at the same time the importance of the bucco-pharyngeal respiration is 
increased.” 
It appears to the writer that Camerano’s conclusions need to be 
tested by further experiments, especially the part referring to the res- 
piration, for the area of the dermal surface far exceeds that of the 
buceo-pharyngeal cavity, and the skin is also very richly supplied with 
blood vessels which are so close to the surface that it would appear 
as if the gases of the blood and air might be readily interchanged. 
It is hoped that time will permit of some experiments on this point 
during the coming year. 
As to the second question, whether there is any appreciable modifi- 
cation of the heart in these lungless salamanders, nothing whatever has 
been published. 
It is the object of this paper to call attention to the fact that there is 
a difference in the heart of those salamanders that do not have lungs 
and those which do have them. So far as I have examined, it is possible 
to distinguish between the two forms by examining the heart alone. 
In order that what is said on this point may be clearly under- 
stood by every one, and in order to bring out the differences between 
the two more sharply, if possible, I wish first to recall to mind the 
structure of the Amphibian heart and then contrast with it the rela- 
tions as found in the heart of a lungless individual. We may take 
Huxley’s description of the Amphibian heart as our standard of com- 
parison. In his Anatomy of Vertebrates he says: “ The heart presents 
two auricles, a single ventricle and a bulbus arteriosus. A venous - 
sinus, the walls of which are rhythmically contractile, receives the 
venous blood from the body and opens into the right auricle. The left 
auricle is much smaller than the right and a single pulmonary vein 
opens into it.” In regard to the septum of the auricles, he says that 
“it is less complete in Proteus, Siren and Menobranchus (Necturus) 
than in other Amphibia. In Menobranchus the septum is reduced to 
little more than a wide meshed network of branched muscular bands, 
and in Proteus the existence of a septum is doubtful.” 
The heart of our common Newt (Diemyctylus viridescens) Fig. 1 or 
of the large yellow-spotted salamander (Amblystoma punctatum), for 
examples, corresponds perfectly with Huxley’s description. In both of 
these forms the auricular septum is perfectly complete, the cavities of 
the auricles being entirely separated, except just at the auriculo-ven- 
tricular aperature, at which point the two auricles communicate with 
each other to some extent. 
In Necturus, the septum is more or less fenestrated and, according 
to Huxley, it is very incomplete in Proteus and Siren, but in all of the 
