842 



Mr. p. e. seddaed osr the 



[Bee. 3, 



the base of lung behind it and then curves back on the anterior 

 face of the lung, where it opens. The various membranes which 

 in Xenopus connect together the lung with the oviduct, and the 

 lung with the stomach, and each of them with the parietes, form a 

 closed sac lying beneath the stomach. The proximal section of 

 the oviduct lies on the outer wall of this sac. As in Pipa, the 

 heart and pericardium are enclosed in a membranous sac. 



We now come to the diaphragm, by which I understand the 

 muscles which are particularly related to the lung and oesophagus. 



Pig. 1. 



Interior of abdominal cavity of Xenopus. 



L, lung ; m.'p, musculus pulmonum proprius ; a, branch of obliquus internus ; 



gl, glutjBus. 



The muscular fibres are, as in Pipa, derived from three sources : — 

 (1) There is first of all a special muscle whose main concern is 

 with the lungs and oesophagus. This is, I believe, not merely the 

 analogue, but the homologue of the " musculus pulmonum proprius^^ 

 as Mayer termed the muscle which I have illustrated in figs. 1 and 



