OCR Text |
Show 692 MR. GERARD W. BUTLER ON THE [Nov. 19, describes Snakes (as known to him) as having but one lung1. W e find this view repeated without qualification so late as 1805 in a work for which Cuvier is responsible2. It would seem that Nitzsch [1808] was the first to describe the rudiment of the second lung (which, be it noted, he rightly speaks of as the left lung) in the Common Snake (Tropidonotus natrix), and to suggest that this rudiment would probably be found in many other Snakes (l)3. Since 1808, thanks to such workers as Meckel, Cuvier, Duvernoy, Stannius, and Cope, our information on the subject has been largely augmented. In a sense it may be said that, excluding details, there is little in this paper which has not been stated or hinted by some one previously. But it is equally true that there is little here which has not been as categorically denied by some one else of equal authority. It has thus happened that an interesting generalization has so far been missed. This is doubtless in part due to the fact that no one person has given special attention to the matter in all the groups of animals concerned, but in part also to error of interpretation, or error or looseness of description on the part of observers, and in part perhaps to want of caution on the part of compilers when summing up. However this be, it seems well to have the facts placed clearly on record now. W h e n studying the pleuroperitoneal spaces and membranes of Lizards, Snakes, & c, in the years 1889-1892 4, I of course had to note the relations of the lungs, and I was much struck by the fact that whereas in the Amphisbaenidae it was always the right lung that was reduced or absent, in Snakes and in other Snake-like Lizards it was the left. W h e n I came to enquire what had previously been written on the subject, I found that there was no satisfactory summing up of the whole matter, and that so far as separate animals or groups of animals were concerned, while some previous statements harmonized with my observations, others of equal authority ran counter to them, while, thirdly, many writers did not commit themselves one way or the other. I have accordingly been over my old observations, and supplemented them by others, with the result of only confirming and widening the generalization at first arrived at, which is-[I of course speak only of the animals examined, see lists, § VI.]-that the Amphisbcenidce stand alone 1 Aristotle's ' History of Animals' (R. Creswell's translation in H. G. Bohn's «• Classical Library " ) , Book ii. chap. ii. § 12, p. 44 (London, 1862). 2 'Lecons d'Anatomie comparee de Georges Cuvier, recueillies et pubises sous ses yeux par G. L. Duvernoy,' torn. iv. pp. 323 & 347 (Paris, 1805). 3 See Bibliography at the end of this paper. Throughout the paper the large numbers in brackets inserted in the text refer to the corresponding work in the list at the end. 4 Proc. Zool. Soc. 1889, pp. 4F2-474, and 1892, pp. 477-498, |