166 BULLETIN UNITED STATES GEOLOGICAL SURVEY. [Vol.Y. 



black; in the pelage being -^liollj' soft and woolly, the long ligliter- 

 tipped hairs having not yet appeared. The sides of the neck and the 

 whole lower snrface are uniform grayish-white, with no separating band 

 cutting oif the white of the chin from that of the throat. Lower surface 

 of the tail for two inches at the base yellowish- white, crossed distally by 

 two dark bars. In other respects, the tail is colored uniformly with the 

 back, and shows no other trace of annulations. It consequently appears 

 that in very young individuals the tail may be either entirely without 

 annulations or have them quite conspicuous. The face i)resents the 

 maximum extension of white, and agrees exactly with the very white- 

 faced adult example from Mazatlan alreatly described. 



In the series of specimens above described there is a complete inter- 

 gradation from the light grayish fulvous example from the Lower Eio 

 Grande to the blackish-brown specimens from Central America, though 

 simi)ly an increased intensity southward in the coloration. At the same 

 time, there is a wide range of piu^ely individual variation in the size of 

 the white face-marks, and especially in the coloration of the lower sur- 

 face of the anterior half of the body. As previously stated, there appear 

 to be no well-marked sexual dift'erences of color. 



Skull. — A series of six adult skulls of this species (four males and 

 two females), and three others from half-grown examples, shows that 

 the skull varies greatly with age and sex. None of the male skulls are 

 very old, the molar teeth being unworn, while one of the female skulls 

 has the tubercles of the molars wholly worn away. Yet in this last the sa- 

 gittal crest is wholly undeveloped, while the middle-aged males have well- 

 developed crests, varj'ing from 5 to 11 mm. in height. The male skulls 

 are also larger, with much larger canines and more heavily developed and 

 more widely spreading zygomata. The male skulls vary considerably in 

 size, the smallest having a length (from front edge of intermaxillse to pos- 

 terior border of occipital condyles) of 119 mm. and a breadth (at the point of 

 greatest expansion of zygomata) of 77 mm., against, respectively, 138 mm. 

 and 81 mm. in the largest. The largest (but not the oldest) female skull 

 has a length of 123 mm. and a width of G5 mm., showing that as regards 

 the length of the skull some of the females exceed in size some of the 

 males. The average of four male skulls, however, gives a length of 

 129 mm. and a width of 79 mm., against, respectively, 122 mm. and 63mm. 

 for the two female skulls. In the females, in addition to the very much 

 smaller size of the canines and the entire absence of a sagittal crest, the 

 zygomatic arches are much weaker and nmch less widely divergent. 



General History and Sy^nonymy. — As already stated in the gen- 

 eral history of the subject, the present species was described by Brisson 

 in 1756 under the name "Le Coati-Mondi," and was redescribed and 

 figured by Buffon in 1760 as " Le Coati bruu." On the latter was ex- 

 clusively based Linne's Viverra narica. Although the habitat of the 

 specimens described is not stated by either of these authors, and was 



