~Artibeus jamaicensis jamaicensis~ Leach.--A female (61088) obtained on June 18, 1954, by Albert A. Alcorn, from 32 mi. SSE Culiacan (24 deg.26', 107 deg.07'), Sinaloa, extends the known range of the species approximately 415 miles northwestward from 2 mi. N. Ciudad Guzman (19 deg.43', 103 deg.28'), Jalisco. Two other females (61089-61090) from central Sinaloa, collected on June 19, 1954, by A. A. Alcorn, are from 1/2 mi. E Piaxtla (23 deg.51', 106 deg.38'). Each of the three specimens contained a single embryo. The embryos (in the order the specimens are listed above) measured 28, 26, and 25 millimeters. The Sinaloan specimens are both paler and browner than specimens from Jalisco and from eastern Mexico, and the facial stripes are more distinct, being as distinct in one specimen (61088) as in any of the _Artibeus lituratus_ reported here. Four additional specimens from Jalisco are: 34232-34235, 3 males and 1 nonpregnant female taken by J. R. Alcorn at Hacienda San Martin (20 deg.18', 103 deg.30'), 18 mi. W Chapala, 5000 feet, on July 12, 1949. Each specimen of _A. jamaicensis_ listed above lacks epiphyseal sutures and both an upper and a lower third molar on each side. In size, coloration of ventral pelage, and configuration of skull, the specimens agree with the description of specimens from Guerrero and differ from other species as reported by Lukens and Davis (1957:7, 9). Minimum and maximum measurements in millimeters for the three _A. jamaicensis_ from Sinaloa, followed by corresponding figures for the four from Jalisco, are: total length, 80-82, 82-84; length of hind foot, 15-16, 16-17; length of ear, all 20, 20-21; length of forearm, 54.7-55.9, 54.7-58.5; greatest length of skull, 26.6-27.3, 26.5-28.2; condylocanine length, 22.6-23.2, 22.5-23.9; lambdoidal breadth, 13.9-14.5, 13.7-15.1; and postorbital constriction, 6.2-6.6; 6.3-6.7.