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Show 5 2 8 MR. F. E. BEDDARD ON TJIE VASCULAR AND [May 1, relations of the tracheal to the thoracic lung, bears the same relation to Tarbophis as does Coluber corais to e. g. Coluber melanoleucus. Finally, I have to point out that the bronchus does not extend very far down the functional lung. The bronchial gutter, which is quite flattened out and not gutter-like as it is in Coluber *, reaches back to a point not more than half an inch behind the apex of the heart. In a fresh example of Boodon lineatus the conditions of the lung were very plainly visible on opening the body. The limits between the vascular and the anangious regions of the respiratory organ were easily mapped. The trachea was seen to be provided dorsally with a tracheal lung, the cells of wThich were especially plain and presented the appearance, before the trachea was split up, of bubbles of air lying between the ends of the tracheal rings. At a level with the commencement of the ventricle, this tracheal ring took on a red hue, this part being vascular. The vascularity of the lung was seen to continue down about an inch along the liver, before the middle of which it ceased to be visible. The bronchus is not, in this species, continued far down the lung. It ceases, in fact, at the very commencement of the thoracic lung. A careful examination failed to reveal any trace of a second rudimentary lung. There was no perforation of the open bronchus at the end of the heart. Neither is there any forward extension of the functional lung headwards. The lung of this Snake is therefore primitive in that it has retained considerable traces of the tracheal lung, but modified in the entire absence of a second lung and of a forward extension of the lung headwards. A second specimen showed identical characters. Sepedon hcemachates.-In view of its relationship to the Hamadryad, I have been particularly anxious to examine this Snake, which, however, shows only slight resemblances to the peculiar precardiac diverticula of the windpipe in Ophiophagus +. The single lung-I have been unable to find a rudimentary lung t- commences to be vascular in the region of the heart and continues to be so a little distance down the liver. The lung-tissue does not, however, abruptly end or begin anteriorly ; it commences gradually at about on a level with the auricles of the heart, this portion being the equivalent of the tracheal lung of other species, though not vascular. In front of this again the ends of the tracheal rings are separated by a very wide membranous interval, fully as wide as the true thoracic lung, and forming an air-sac continuous with the lung which extends up to the head. The arrangement is, in fact, like that of Coluber corais described above. The tracheal gutter does not extend far into the thoracic lung and is continued a little way further by a fibrous band. The new facts which have been here detailed seem to afford * See p. 522. f P. Z. S. 1903, vol. ii. p. 332. is o n f ilU0*EdWardS (PhyS' €t Anat* C°mp- ii‘ 1857' p' 308 footnote) states that there |
