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Show single renal artery to each kidney, a fact quite independent of the size of the kidney, is confirmed by several fresh examples. (5) More evidence is adduced to show that among the Boine Snakes the relations of the anterior abdominal vein to the afferent renal veins are those of the Lacertilia ; and it has been pointed out that (in Boa constrictor) these veins may be symmetrical in their origins in spite of the asymmetry of the kidneys. This is, of course, a further point of likeness to (presumably) primitive conditions. (6) In considering the relations of the more or less double anterior abdominal vein of the Boidae to the same vein or veins in other Sauropsida, it is (or may be) important to note that, at any rate occasionally (Boa constrictor), the left trunk is associated by transverse connections with the epigastric vein, and the right trunk only with the fat-body, and not at all with the epigastric vein. (7) Attention is directed to the intercostal arteries of Erythro-amprus, which appears to offer an intermediate condition between the Boid Snakes and the Viperidse. To others it has appeared that the Viperine Snakes are to be derived from the Opistho-glyplious Colubrines. (8) The structure of the genus Corallus on the whole confirms the current view that it is to be referred to the Boine section of the Boidse. (9) The existence of rudiments, apparently functional, of the tracheal lung are more numerous in the Ophidia than would be inferred from a consultation of the literature of the subject. Such traces have been described above in a number of species where they have not been hitherto recorded. (10) The prevalence of at least traces of a tracheal lung in so many and often not nearly related families is an argument for considering that its existence is a retention-that it has not been acquired separately in the several genera or families where it occurs, but has rather been lost in those genera, &c., where there is now no tracheal lung. (11) The view of Prof. Cope that the tracheal lung is a further extension of the Lizard-like pocket extending beyond the entrance of the bronchus, which is found in the functional lung or lungs of many Snakes, cannot be correct, since this pocket coexists with remains of the tracheal lung in some forms. (12) The structure of the lungs offers facts of detailed classi-ficatory value; but the wide prevalence of the tracheal lung or remains of it does not tend to support the scheme of classification set out by Prof Cope in its entirety. 5 3 2 TIIE VASCULAR AND RESPIRATORY SYSTEMS IN OPHIDIA. [May 1, |
