To the list given by Koopman and Martin (1959:9) of neotropical genera known to range farther north on the west coast of North America than on the east coast there can now be added _Artibeus_, _Sturnira_ and _Chiroderma_ (as noted above), _Anoura_, _Choeronycteris_ and _Leptonycteris_ (Hall and Kelson, 1959:119, 120, 122; Hoffmeister, 1959:18), and _Liomys_ (Hall and Kelson, 1959:536). In view of these additional genera, and others that almost certainly remain to be discovered farther north on the west coast, the suggestion by Koopman and Martin (1959:11) that species inhabiting humid tropical habitats, in general extend farther north on the east coast of Mexico than on the west coast may need to be reconsidered. On the west coast, areas of more humid tropical vegetation and climate are more distant from the coastline as one proceeds northwestward from Nayarit to Sonora. The broad band of humid tropical vegetation along the coast is progressively reduced in width, and crowded back against the mountains, and still farther north consists of only small scattered remnants that are difficult to visit, in the bottoms of deep canyons. LITERATURE CITED COCKRUM, E. L. 1955. Reproduction in North American Bats. Trans. Kansas Acad. Sci., 58:487-511. DALQUEST, W. W. 1953. Mexican bats of the genus _Artibeus_. Proc. Biol. Soc. Washington, 66:61-66. DAVIS, W. B. 1958. Review of Mexican bats of the Artibeus "cinereus" complex. Proc. Biol. Soc. Washington, 71:163-166, 1 fig. in text. HALL, E. R., and KELSON, K. R. 1959. The mammals of North America. The Ronald Press, N. Y., Vol. I, xxx + 1-546 + 1-79 pp., 312 figs. and 320 maps in text, unnumbered figures in text. HOFFMEISTER, D. F. 1959. Distributional records of certain mammals from southern Arizona. Southwest. Nat., 4:14-19, 1 fig. in text. KOOPMAN, K. F., and MARTIN, P. S. 1959. Subfossil mammals from the Gomez Farias region and the tropical gradient of eastern Mexico. Jour. Mamm., 40:1-12, 1 fig. and 2 tables in text. LUKENS, P. W., JR., and DAVIS, W. B. 1957. Bats of the Mexican state of Guerrero. Jour. Mamm., 38:1-14. _Transmitted August 18, 1960._ * * * * * Transcriber's Notes Both variations, Mexico (3 times) and Mexico (4 times) are used. Italicized text is shown within _underscores_. Bold text is shows within ~tildes~.