| OCR Text |
Show 1890.] ANATOMY OF THE CONDOR. 145 valve, otherwise wanting in the heart of Chung a ; its position 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 burmeisteri. V, cavity of left ventricle ; A, fleshy bridge uniting valve to free wall of ventricle ; 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 contraction of the parietes of the heart. Chunga does not seem to be a bird in which any such supplementary apparatus is greatly needed. Hence its importance may be more morphological than physiological. The fact that in the two lowest mammals (Echidna and Ornithorhynchus) 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 coincidence ; and the resemblance is more striking if we admit that the part of the valve lving to the left of the fleshy bridge in the Bird's heart has its equivalent in the parts lettered I. a. c. in Lankester's account of the heart of Ornithorhynchus and Echidna '. 1 Loc. cit. |
