Scale Reduction Studies in Certain Non-Colubrid Snakes

Abstract

JN a recent paper on scale row reduction in snakes we have attempted a critical analysis of the general subject, based mainly on snakes of the family Colubridae. We have now examined 50 specimens of the various non-colubrid families Boidae, Pythonidae, Elapidae, Crotalidae, and Viperidae. On the whole we find no fundamental differences in the reduction patterns of these families from those that characterize the Colubridae. We are again grateful to the authorities of Field Museum of Natural History for permission to consult the reference collection and for laboratory space. Messrs. Karl P. Schmidt and Clifford H. Pope have continued their helpful advice and criticism. In species with an unusually large number of scale rows the reductions are frequently irregular and assymetrical, occurring at different levels on the body, as notably in the colubrid Spalerosophis maximus. This is naturally true of the boas and pythons, in which there may be as many as 95 scale rows. In species of these families with a low number of scale rows, the reductions may very nearly correspond on both sides of the body. In species with a large number of scale rows the reductions often become more symmetrical on the posterior part of the body, where the number of rows de-