100 NORTH AMERICAN MUSTELID^. 



convex, strougly declivous. Pterygoids developing large hamular processes. 

 Bullao aiulitorijB nicked by orifice of meatus. Skull scarcely constricted near 

 the middle, where, if anything, it is broader than rostrum ; postorbital pro- 

 cesses poorly developed. Sectorial tooth of upper jaw as in Cynomyonax. 

 Back molar of lower jaw of ordinary size, circular, developing irregularities 

 of the crown. Animals rather large, comparatively stout-bodied, less length- 

 ened, with rather bushy, tapering tail, and low, orbicular ears ; pelage 

 long and loose, instead of close-set, variegated above, or there not notably 

 darker than below ; do not turn white in winter. Palmar pads separate. 

 Toes not semipalmate. Terrestrial in habits. The species confined to the 

 Old World. 



4. LuTREOLA*. — The Minks. — Skull of adult developing sagittal crest and 

 muscular impressions. Frontal outline nearly straight and scarcely declivous. 

 Pterygoids with strong -hamular process. Bullae auditorise notably less 

 inflated than in the foregoing, prolonged into a somewhat tubular meatus, 

 not nicked at orifice. Constriction of skull and development of postorbital 

 processes intermediate in degree between FiUorius proper and Cynomyonax. 

 Sectorial tooth of upper jaw with its outer border concave, owing to devel- 

 opment of a strong antero-exterior spur, which lies out of the axis of dentition, 

 and forms with the antero-interior cusp (present in all Miistelince) a rather 

 open V, into which the antecedent premolar fits, the antero-internal process 

 developing to a conical cusp. Back lower molar as in Putorius proper. 

 Animals of large to largest size in the genus, stout-bodied, rather long and 

 very bushy tail, cylindrico-tapering ; pelage moderately loose, but thick, 

 to resist water, very bristly and lustrous, dark-colored, unicolor or only 

 varied with irregular white patches on under parts ; no seasonal changes of 

 pelage. Ears very low. Feet semipalmate, natatorial. Palmar pads with- 

 out hairy intervals. Habits highly aquatic. Species common to both hem- 

 ispheres. 



The first of these subgenera is represented in North America 

 by several species, some of which are not clearly- distinguished 

 from their congeners of Europe, while another is specifically 

 identical with an animal which ranges through Central into South 

 America. The second and fourth each contain a single North 

 American species, as far as known, the fourth having a closely 

 allied European congener ; while the second, peculiar to Amer- 

 ica, is the nearest analogue of the third, which has no exact 

 American representative. 



The North American species of Putorius at large may be 

 determined by the following analysis of subgeneric and specific 

 characters : — 



* Eiynt.—" Lutreola ", " Little Otter " — diminutive form of the Latin hiira, 

 an Otter, which the Mink much resembles. For von Marten's exposition of 

 the word Intra in its several forms, and discussion of the philological ques- 

 tions involved, see p. 29. 



