236 
JOURNAL OF MAMMALOGY 
Sigmodon hispidus exsputus^ subsp. nov. 
Type, adult male, skin and skull, 18,100 Mus. Comp. Zoology, from Big Pine 
Key, of the southern Florida Keys, collected April 16, 1920, by Winthrop S. 
Brooks. 
General characters. — Small, about the size of S. h. spadicipygus but with a 
proportionally longer tail; at once distinguishable from the latter race by the 
general pale ochraceous tone of the dorsal surfaces of head and body, with slaty 
rather than blackish bases to the hairs, and the clearer white of the belly with 
the bases of the hairs less prominent and of a paler slaty gray. 
Description. — General color of the dorsal surfaces pale ‘‘ochraceous buff,’’ 
clearest along the sides of the cheeks and body, becoming slightly deeper on the 
rump. The long overlying hairs of the pelage on the lower half of the back are 
whitish tipped instead of black throughout as in the mainland form. The con- 
cealed bases of the hairs are slaty instead of blackish, and lack the indistinct 
brownish cast of spadicipygus. Belly nearly clear white, the color rather sharply 
marked off at the sides, the pale slaty bases of the hairs showing through but 
little, in contrast to the mainland form in which the transition from the color 
of the back to that of the belly is less sharp and the belly much tinged with 
brownish and slaty where the bases of the hairs show through. Fore feet above 
like the sides; the hind feet dusky with a sprinkling of dull-whitish hairs. Tail 
dusky, with short sparse hairs which are blackish above, faintly whitish below. 
The skull is essentially as in S. h. spadicipygus, but a very little slenderer. 
Measurements. — ^The collector’s field record gives the following: total length 
259 mm., tail 117, hind foot 33.5, ear 18.5. The skull measures: greatest length 
36.5 mm., basal length 32, palatal length 28.5, nasals 15, upper tooth row 6, lower 
tooth row 6, zygomatic width 20.5, mastoid width 15. ^ 
Remarks . — In a series of twentj^ excellent skins from Cape Sable and 
Flamingo, collected in late March and early April and representing 
spadicipygus, there is but one (Bangs Coll. 4490 from Flamingo) that 
closely resembles the island race in its color. It is at once distinguish- 
able, however, by its slightly brownish or rusty tint especially on the 
lower back, by the blacker bases of the hairs, and by its much shorter 
tail. In eighteen specimens of S. h. spadicipygus the collector’s field 
measurements indicate that the tail averages 37 per cent (extremes 
35 to 41) of the total length, whereas in the two island specimens it is 
much longer, 45 per cent in each, a difference at once obvious to the 
eye. Both specimens were shot by Mr. Brooks in the day time, while 
they were running actively about in the scrub. 
^ exsputus, cast out, banished, exiled. 
