ON THE HEART OF LUNGLESS SALAMANDERS.i 



HENRY L. BRUNER, Ph.D. 



In the American Naturalist iox 1896 Hopkins (14) announced 

 the discovery of a septum atriorum in the heart of certain lung- 

 less salamanders. Beginning with the heart of salamanders 

 with lungs, Hopkins calls attention to various parts of that 

 organ, but omits entirely the valve at the sinus-atrium opening. 

 Later, however, in his study of the heart of the lungless sala- 

 manders, Hopkins observed this valve, but considered it to be 

 a rudimentary septum atriorum. The conclusion of Hopkins, 

 that such a septum is present in lungless salamanders, has 

 been accepted by Bethge (i), but apparently without personal 

 investigation. A similar view occurs also in the recently pub- 

 lished "Vertebrate Zoology" of Kingsley (17). On account 

 of these facts I wish to report some observations which I had 

 already made on the heart of lungless salamanders before the 

 paper of Hopkins came to my notice. The investigation was 

 undertaken at the suggestion of Professor Wiedersheim, in 

 whose Institute in Freiburg the work was begun, and to whom 

 I am indebted for the necessary material. 



Historical. 



The general structure of the heart of amphibians was de- 

 scribed by Rusconi (29), Briicke (7), and Stannius (28), about 

 the middle of the present century. 



An excellent account, published somewhat later, is that of 

 Fritsch (11), whose work is made, to a considerable extent, the 

 basis of the description in Bronn's "Amphibien," where also 

 the figures of Fritsch are reproduced. In his work on the frog, 

 Fritsch studied the structure of the ventricle and the arrange- 



1 A short abstract with the above title was published in the Proceedings of the 

 Indiana Academy of Science (3) for 1897. Later a similar notice appeared in the 

 Anatomischer Anzeiger (4). 



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