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Show 700 MR. GERARD W. BUTLER ON THE [Nov. 19> When, as is commonly the case, the various longitudinally disposed viscera (the alimentary canal, liver, lung, and the longitudinal vascular trunks) between which they run are displaced from the positions they occupy in other animals, the course of these vessels is correspondingly circuitous. In fact, as the figures [PI. X L . figs. 2-9], show, in passing from the vertebral column to the mid-dorsal line of the liver, they frequently have to describe a semicircle to pass round tbe mesial or left side of the larger right lung, which commonly encroaches considerably on the left half of the body. Without very careful dissection the student may not in every uninfected spirit-specimen that comes into his hands find all the blood-vessels above referred to. I have not done so myself. In some cases I have found them all; in o'thers now some series of vessels, now others; but in all the Snakes in m y list I have obtained sufficient evidence from the blood-vessels to make it clear that the larger or only lung is the homologue of the right lung of other vertebrates. (b) Some Remarks on Prof. Cope's Papers on the Lungs of Snakes. Having thus presented what I believe to be without any shadow of doubt the correct view of the matter, and pointed out a simple means by which anyone may test the truth for himself, I think all that remains for m e to do further is to explain away tbe apparently conflicting evidence of tbe figures in Prof. Cope's papers above mentioned [(7) and (8)]. I say the conflicting evidence of his figures, because in more than one place [(7) pp. 218 and 219, and (8) pp. 836 and 838] Prof. Cope expresses himself so as to suggest that he did not wish to commit himself to a use of the terms " right " and " left " in a morphological sense, but that he rather wished to designate those lungs which [in his opinion] are situated more to the right or left side of the animal. But when in his figures he labels the lungs E.L. and L.L. respectively, and in his explanation of the plates states that these letters stand for right lung and left lung, I think that the reader does carry away the impression that by these he means the lungs which are the homologues of the right and left lungs of other animals ; and this impression will be deepened by certain passages in the papers [e.g. (7) p. 223 and (8) p. 838]. N o w if we except Typhlops [(7) pi. xi.], which is one of the very few Snakes in which Cope will allow the " left" lung to be absent or smaller than the " right," we find that Cope in all his plates calls the best developed lung the " Left" lung and the smaller or rudimentary one the " Eight " ; and thus his figures are, as they stand, decidedly misleading. While saying this I would, however, cordially acknowledge that the figures appear to have been carefully and truthfully drawn from the dissections, and such being the case, a comparatively brief cross examination of the figures brings out the truth. Those who have carefully dissected this part of Snakes, and |