I follow Davis (1958:165) in treating A. aztecus and A. toltecus as distinct species. Differences between the two are discussed in the preceding account of toltecus.
One specimen examined (AMNH 146980) is distinctly larger than the others here assigned to A. aztecus, but does not exceed the maximal measurements given by Davis (loc. cit.) for the species. This specimen also has a narrower M2, and relatively and actually narrower braincase than other specimens (see measurements).
Specimens from Rancho del Cielo were collected in a limestone cave in the cloud forest. A female taken on July 2 carried a small embryo and another obtained on August 14 had an embryo that appeared to be nearly ready for birth.
Measurements.—Respective external and cranial measurements of three males (AMNH, uncatalogued) and a female (AMNH 146980) are as follows: total length, 58, 65, 66, 73; length of hind foot, 13, 12, 12, 13; length of forearm, —, 43, 40, 41; greatest length of skull, 21.6, 22.4, 21.5, 23.0; zygomatic breadth, 13.0, 12.8, 13.0, 12.4; least interorbital constriction, 5.2, 5.7, 5.5, 6.0; length of maxillary tooth-row, 7.0, 7.1, 6.9, 7.1; breadth of braincase, 10.0, 9.8, 10.0, 9.5.
Records of occurrence.—Specimens examined, 7, all from Rancho del Cielo, 3300 ft., (AMNH).
Enchistenes hartii (Thomas)
Little Fruit-eating Bat
1892. Artibeus hartii Thomas, Ann. Mag. Nat. Hist., ser. 6, 10:409, November, type from Trinidad, Lesser Antilles.
1908. Enchistenes hartii, Andersen, Proc. Zool. Soc. London, 2:224, September 7.
Distribution in Tamaulipas.—Known only from Aserradero del Infernillo.
Enchistenes hartii is known from Tamaulipas only by the cranium reported by Goodwin (1954:5), and this is the northernmost known occurrence. The bat has not been reported from any other Mexican state bordering on the Gulf of Mexico.