146 BULLETIN 43, UNITED STATE8 NATIONAL MUSEUM. 



lu the immature iudividual the hair is without the basal bhick. On 

 the dorsum the tips are more ashy than in the adult. In some speci- 

 mens the gray tints predominate along the entire hair. In other exam- 

 ples the basal parts are light brown or reddish brown. On the venter 

 the parts below the line of the head are entirely white over the chest 

 in very young animals, the abdomen being naked. In older forms the 

 basal parts are brown; tlie sides of the trunk are lined nearly as far 

 back as the spine, much as in GMlionycteis davyi. The ears are hairy 

 with the exception of the tips. The deep conch, as it turns on the neck, 

 is heavily covered with hair of the dorsal hues. The hair on the inter- 

 femoral membrane and the white spots on the first and fifth meta- 

 carpals are as in the adult, but the hair along the forearm is absent. 



In an embryo 20""" long, from vertex to ])ubis was, with the exception 

 of a little hair on the lower lip, naked on the under surface of the body. 

 The color of the skin Avas of a delicate salmon. On the back, in- 

 cluding the interfemoral membrane, the hair was short, uniform, and of 

 a chestnut-brown color, with ashy tips, excepting the margin of the 

 trunk, where the hair was white. On the head a fold extended ob- 

 liquely forward and inward and almost joined a corresponding band 

 from the ear of the oi)posite side. The skin of the side of the neck over 

 the position of the tendon of the occipito-pollical muscle Avas conspicu- 

 ously raised. In another example of the same size the coloration was 

 the same, excepting that the junction of the side of the neck and the 

 region of the shoulder (ventral asi)ect) was covered with short, white 

 hair. 



Variations. — No. OOoO U. S. N. M.; skin, nearly adult; without 

 locality, is of a uniform gray at the subtip. The absence of the 

 characteristic russet and chocolate tints easily distinguishes this form. 

 It probably is from a northern locality. The specimen is in bad con- 

 dition. Specimen Xo. 11153 U. !S. X. M., skin, from Arizona or Xevada, 

 Wheeler's expedition ( f ), does not appear to differ from the eastern ex- 

 amples. The Mexican and California varieties are smaller, with a red- 

 der color posteriorly and a gray hue anteriorly. The shoulder tuft is 

 more distinctly ventral. The ventral aspect of the interfemoral mem- 

 brane is less hairy at the base than are the northern forms, while the 

 hair about the interiiu- extremity extends farther on the endopatagium. 



An example from Guanajuato, JVIexico, in the collection of Mr. II. A. 

 Ward (No. 14290), resembles A. frantzii, Peters. The venter is cov- 

 ered with silky fur, plumbeous at basal half, and whitish or gray at 

 apical half. The fur on the membrane is grayish. 



Two examples from Florida, in the Museum of Comparative Zoology, 

 are darker throughout than the above description. The external basal 

 lobe was larger, the first phalanx of the second shorter, finger and the 

 external border of the auricle slightly emarginate. The specimens 

 are immature and much mutilated with shot. They may represent 

 A.jjfeiffvri ( ?). Mr. C. F. Mayuard, /. c, mentions that specimens from 



