Another day the large reticulated python seemed to intentionally gratify my curiosity by affording me a most leisurely and excellent opportunity for observation. His head was raised, and so close to the glass that the process of swallowing could be watched conveniently. The final swallow, or successive efforts at the last were, as usual, attended with frequent yawns. The glottis, as could on these occasions be distinctly seen, was repeatedly opened and closed, and after being extended beyond the mouth, it gradually resumed its natural position. While the prey occupied the entire space between the gaping jaws, one could see the air-tube pushed forward _beneath_; but as by degrees the duck disappeared down the throat, the interior of the mouth could be better and better observed. In this large snake the membrane or skin was too thick to enable one to discern rings as in the little _Coluber_; but as the larynx is merely the upper part of the trachea, and as the glottis is the mere membranous opening to the larynx, it seems evident that the windpipe itself is also extensible, the windpipe being, indeed, the only portion of the air-tube sufficiently firm and resisting to aid the purpose of respiration under such conditions. The exact distance which the tube is extended cannot be accurately stated. It would not be equally protruded in snakes of different sizes nor under different conditions. Broderip saw it ‘as much as a quarter of an inch.’ Bingley, an earlier and a less safe authority, says ‘the windpipe projected _three inches_ beyond his jaws.’ The keeper at the Gardens thought he had sometimes seen it ‘as much as two inches in the largest snakes;’ and my own impression was, one inch, at least, in the python, and almost that in the large vipers. It is undoubtedly one of those interesting features worthy of further investigation, and one is surprised that more accurate information regarding it has not appeared in our later encyclopedias and in the ‘Proceedings of the Zoological Societies.’ So long ago as 1826, it was observed and confirmed by the distinguished author of _Zoological Researches_, and _Leaves from the Notebook of a Naturalist_. The author of _British Reptiles_, who conducted the _Zoological Journal_ when Mr. Broderip contributed the valuable paper above quoted, added a note by special request, stating that his own ‘not unfrequent observations have on every point been completely confirmatory of those above recorded’ by W. J. Broderip, Esq. A very good account of the whole is quoted in the _Penny Magazine_, 1836, and we are therein further enlightened by reading that Joseph Henry Green, Esq., F.R.S., in one of his lectures at the Royal College of Surgeons, alluded to Broderip’s paper ‘On the Mode in which Constrictors swallow their Prey,’ and which had drawn his attention to the statement about the larynx, and led him to examine the mouth of a snake.