68 XOKTIl AMERICAN FAUNA 6 0, FISH AND WILDLIFE SERVICE 



tensiiying gonoral dark tone; top of head clearer gray, heavily mixed 

 with hlack, producing a somewhat grizzled effect, the black predom- 

 inating; black facial mask extending downward on median line to nose 

 and upward to middle of forehead ; white supraorbital lines short and 

 narrow, ending under ears instead of continuing posteriorly to sides of 

 neck as in shujcldti and more northern forms; sides of muzzle, lips, and 

 chin white; under parts in general thinly overlaid with buffy white, 

 the underfur light brownish, sparse and only partially concealing the 

 skin beneath; throat patch brownish black; ears grayish; black post- 

 auricular spots small, tending to blend with dark tone of back; fore- 

 arms dull grayish, becoming soiled whitish on feet; outer surfaces of 

 hind legs similar to sides of body, becoming brownish black near heels 

 and soiled whitish on feet; tail above with about seven blackish rings, 

 rather indistinct near base, and a black tip, alternating with rich 

 ochraceous buffy rings, tending to blend along median line below. 



Cranial characters. — Skull characterized by thin-walled, delicate 

 structure, with weakly developed sagittal and lambdoid crests. Most 

 closely resembling that of P. I. crassidens, but of lighter proportions; 

 frontal region less flattened; palate much narrower, a character very 

 noticeable in the lesser distance between cheek tooth series; jugal more 

 slender; dentition heavy, much as in crassidens. Compared with that 

 of P. I. shufeldii the skull is decidedly smaller and less massive; frontal 

 region of similar elevation; sagittal and lambdoid crests weaker, 

 thinner and more trenchant; palate narrower; auditory bullae usually 

 smaller; dentition about the same. 



Measurements. — Type: Total length, 840 mm.; tail vertebrae, 310; hind foot, 

 115. Average of four adult male topotypes: 840 (800-870) mm.; 297 (300-340) ; 

 114 (110-120). Average of eight adult female topotypes: 782 (730-790); 300 

 (280-340) ; 1 10 (105-1 20) . Skull: Type and an adult male topotype, respectively : 

 Greatest length, 114.7, 108.3: condylobasal length, 108.4, 102.7; zygomatic 

 breadth, 79.3, 76.2; interorbital breadth, 23.9, 22.5; width of palate between last 

 molars, 19.5, 20.9; least width of palatal shelf, 16, 15.3; maxillary tooth row 

 (alveoli), 41.7, 40.7; upper carnassial, crown length, 7.7, 8.5, crown width, 9, 8.9. 

 Average of seven adult female topotypes: Greatest length, 116.1 (113-122.5); 

 condylobasal length, 109.7 (107.5-115.9); zygomatic breadth, 74 (70.2-80); inter- 

 orbital breadth, 23.9 (22.9-25.3); width of palate between last molars, 19.7 (18.4- 

 21); least width of palatal shelf, 15.2 (14.7-15.7); maxillary tooth row, 43.7 

 (42.7-45.7); upper carnassial, crown length, 9.2 (8.7-10), crown width, 10 

 (9.5-11). 



Remarks. — P. I. dickeyi is the most northern of the known Central 

 American subspecies, all of which are characterized by darker color 

 than their more northern relatives. It appears to be a highly special- 

 ized mangrove-inhabiting race as specimens from the interior only a 

 short distance away are markedly different and nearer to crassidens. 

 In external appearance this subspecies is similar to P. I. crassidens, but 

 the cranial features are quite distinctive. The rusty rufous nape 



