1890.] 



ANATOMY or THE CONDOR. 



145 



valve, otherwise wanting in the heart of Cliunga ; its position in that 

 bird and its connection with the muscle attaching the free valve to the 

 parietes to some extent favour such a supposition, which, however, 

 I am unable at present further to support. In any case the very 

 complicated interior of the right ventricle in Chunga appeared to me 

 to be worth figuring. 



In the figure of the Crocodile's heart (woodcut fig. 1, p. 143) a 

 muscle entering the " membranous valve " at its lowermost point will 

 be noticed ; it appears to be just possible that the muscular processes 

 lettered B in the heart of Chunga (woodcut fig. 2) may be comparable 

 to this. 



Fig. 2. 



Heart of Chunga hurmeisteri. 



V, cavity of left ventricle ; A, flesby bridge uniting valve to Tree wall ol' ven- 

 tricle ; B, C, muscular bands uniting free and septal walls of ventricle. 



Prof. Rolleston associated the presence of a moderator band with 

 very active habits, its use being to increase the effect of the contrac- 

 tion of the parietes of the heart. Chun</a does not seem to be a 

 bird in which any such supplementary apparatus is greatlj^ needed. 

 Hence its importance may be more morphological than physio- 

 logical. 



The fact that in the two lowest mammals (Echidna and Ornitlw- 

 rhynchus) the outer fleshy half of the right auricular valve only is 

 present, as in the Bird's heart, appears to me to be more than a coinci- 

 dence ; and the resemblance is more striking if we admit that the part 

 of the valve lying to the left of the fleshy bridge in the Bird's heart 

 has its equivalent in the parts lettered /. a. c, in Lankester's account 

 of the heart of Ornithorhynchtis and Echidna^. 



^ Log. cit. 



