EXPLANATION OF PLATE XXVII. 



NASUA NARICA MOLARIS Merriam 



Figures all ^ nat. size. 



Lateral view of 6 skulls, 3 male and 3 female, to illustrate variation due 

 to sex and age. Specimens all from Escuinapa, southern Sinaloa, Mexico. 



FIG. i. No. 23984, 9 juv., Jan. 17, 1904. Entire milk dentition still in 

 place, with also permanent m 1 fully functional. 



FIG. 2. No. 23998, c^ juv., Jan. 10, 1904. Same age as specimen shown in 

 Fig. i, with the same condition of dentition. 



FIG. 3. No. 24636, 9 ad., April 28, 1904. A middle-aged female, with the 

 teeth showing only slight traces of wear. 



FIG. 4. No. 23991, cT ad., Jan. 6, 1904. A young adult, slightly younger 

 than the female shown in Fig. 3. 



FIG. 5. No. 23989, very old- 9, Jan. 6, 1904. Similar, in the general 

 contour of the skull, to the middle-aged female, and young adult male, shown 

 in Figs. 3 and 4. Note absence of any trace of a sagittal crest. The great age 

 of the specimen is shown by the worn-out teeth and the heavily ossified condi- 

 tion of the skull. An average example, however, of a very old female. 



FIG. 6. No. 24604, very old <5\ Feb. 7, 1904. Strictly comparable as re- 

 gards age with the- female skull shown in Fig. 5 . Note the great difference in 

 the configuration of the middle region of the skull the form of zygoma, the 

 great depth of the postorbital constriction, and the slight depth of the interor- 

 bital constriction as compared with the same parts in the old female and in 

 the middle-aged male and female, shown respectively in Figs. 5, 4, and 3. 



