920 MR. F. E. BEDDARl) ON TWO SPECIES [DeC. 14, 



enormous and bearing no possible relation to their relative size, 

 for the larger lung is at most twice the size of the smaller. At 

 its extremity the bronchial gutter narrows to almost thread-like 

 proportions. There was no trace that I could discover of a 

 condition like that of CoraUics caninus*, where the semirings 

 become irregular in position and leave tracts of lung substance 

 between them. The bronchus was perfectly continuous as such 

 up to its very end. It is furthermore to be noted that the 

 gutter-like character of the imperfect In-onchus is yeiy marked 

 here. I should imagine, indeed, that it may become functionally 

 a tube within the lung under certain conditions. Under such 

 circumstances the rapid distention of the terminal anangious 

 region of the lung might be effected, for terrifying or other 

 purposes. As in some other snakes, of which particular mention 

 will be made presently, jBoa occidentaUs shows a seam running a 

 considerable distance along the lung which starts from the 

 termination of the bronchus in the larger lung. As is to be seen 

 from an inspection of the accompanying figure (text-fig. 283), this 

 seam appears to be quite independent of the partitions between 

 the alveoli of the lung. It is evidently a structure distinct from 

 them, for in some cases it crosses a definite alveolus at the middle. 

 The seam is, in fact, not merely the coalescence of the walls of a 

 series of alveoli. This fact (i. e. that it is an independent structure) 

 seems to show that the view generally held as to the nature of 

 this seam, namely that it is a rudiment of the bronchus, is the 

 correct view. The seam extends far- into the anangious region of 

 the lung, and, as already mentioned, it is only in this larger lung 

 that it occurs, being absent in the smallei'. 



This seam extends for a distance down the lung which is fully 

 as great as the length of the bronchial gutter. Its diameter is 

 about as great as that of the stouter alveolar walls. But this 

 fact does not permit of any confusion between the structures, nor 

 hinders the accurate tracing of the course of the bronchial seam. 

 For the latter is of a distinctly white colour as compared with the 

 brown colour of the inner surface of the lungs including the 

 walls of the alveoli^ — due to the formalin in which the lung was 

 preserved. Another reason which leads to the easy identification 

 of this fibrous seam throughout its whole course has already been 

 briefly mentioned. The seam appears to cross over the lung 

 alveoli, and is thus evidently not composed of a series of 

 coincident alveolar walls. But more than this can be observed 

 in its relations to the alveolar walls. It will be seen from an 

 inspection of the accompanying figure (text-fig. 283) that the 

 seam does not fuse with the alveolar walls bvit passes above 

 them, and is indeed qvdte independent of them. All this of 

 course establishes on a very firm basis the view that this seam is 

 a real continuation of the bronchus as it appears to be. It has 

 already been mentioned that in the smaller lung there is no trace 



* "A Comparison of the Neotropical Species of Coralhis, &c.," P. Z. S. 1908, 

 p. 135 ; see text-fig. 27, p. 156. 



