_Characters for ready recognition._--Differs from _M. f. olivacea_ in coarser pelage and larger tympanic bullae. _Description._--_Size._--Male: No external measurements available. Female: The type a young animal and no. 2379, an adult from Tarpon Springs, measure respectively as follows: Total length, 375, 378; length of tail, 100, 130; length of hind foot, 40, 44.5. _Externals._--As described in _Mustela frenata noveboracensis_ except that hairiness of foot-soles as shown in figure 20. _Color._--Upper parts (in winter) near tone 3 of Burnt Umber of Oberthür and Dauthenay, pl. 304. Dark spot at each angle of mouth present or absent. Tip of tail black. Underparts Reed Yellow except on chin and usually on legs where white. Upper lips white entirely around. Upper parts of uniform color. Color of underparts extends distally on legs over both sides of feet and on front legs over wrists. Proximal part of tail slightly lighter below than above. Least width of color of underparts, in seven specimens, averaging 41 (extremes 31-52) per cent of greatest width of color of upper parts. Black tip of tail, in each of two females, 45 mm. long; thus slightly longer than hind foot and amounting to 36 per cent of length of tail-vertebrae. The spot at the angle of the mouth is absent in four of the ten specimens and is present on both sides in the other six. _Skull and teeth._--Male (based on an adult from Apopka and the anterior part of an adult from Enterprise): See measurements and plates 16-18. As described in _Mustela frenata olivacea_ except that: Weight, 7.0 grams; basilar length, 49.8. Female (based on an adult from Tarpon Springs, Florida): See measurements. As described in _Mustela frenata olivacea_ except that: Weight, 4.7 grams; basilar length, 44.2; zygomatic breadth more than distance between anterior palatine foramen and anterior margin of tympanic bulla. In comparison with _M. f. olivacea_, the insufficient material of _M. f. peninsulae_ suggests that its skull averages larger and has relatively as well as actually larger and more inflated tympanic bullae. _Remarks._--The first published mention of this weasel seems to have been the original description which appeared in 1894. This description was based on a single specimen sent to Samuel N. Rhoads by W. S. Dickinson, who, in the following year, procured another specimen at Tarpon Springs. So far as known only eight other specimens, as listed under "_Specimens examined_," have found their way into collections of study specimens. H. H. Bailey (1930:1) credits the range of this subspecies as extending south "to the shores of Florida Bay and the Gulf of Mexico, where ever high ground occurs."