DIAGNOSES OF NORTH AMERICAN SUBFAMILIES. 9 



We may finally 8uiii and amplify the differential characters 

 of the foregoing table, with others, in the following expressions, 

 diagnostic of the fi^e subfamilies here adopted : — 



DiAaNOSES OF THE FIVE NORTH AMERICAN SUBFAMILIES. 



1. Musteline. — Teeth of ordinary Oarnivoroas pattern, 38 

 or 34 in number, according to varying number of premolars, 

 whether ^ (Gido, Mustela) or ^—^{Putoriiis)', the number unequal 

 in the two jaws, i^ or ^; incisors constantly ~; canines J^, as in 

 all Mustelidw ; and molars —r^, as in all Mustelichc excepting Mel- 

 livorince. Molar of upper jaw much wider than long; its long 

 axis transverse to the axis of the dental series, longitudinally 

 constricted across the middle. Posterior upper i)remolar (the 

 large "sectorial" tooth) narrow and linear, with a small dis- 

 tinct spur projecting inward from its antero-interior corner. 

 Eostral part of skull moderately produced, sloping in profile, very 

 obliquely truncated, transversely convex, the hind ends of the na- 

 sals more nearly opposite the roots of the zygoma than their fore 

 ends are.* Cerebral i:)ortion of skull comparatively compressed 

 backward, little broader behind than before, with moderately 

 convex lateral outlines. Postorbital processes moderately 

 developed. Anteorbital foramen small, oval or subcircular, 

 presenting upward forward (GiiJo) or more or less downward 

 forward (Mustela, Futorlus). Posterior nares thrown into one 

 common conduit by absence of bony septum. Bony palate pro- 

 duced far back of molars, — half-way (more or less) to ends of 

 pterygoids; interpter^^goid space longer than wide. Audi- 

 tory bull?e much inflated, with moderate constriction of the 

 tubular ineatus.f Little or no expansion of periotic region 

 behind the bulltie, with which the paroccipitals appear in contact. 

 Mastoids little developed, presenting outward or backward. 

 Glenoid fossie shallow, the anterior ledge slight ; condyles never 

 locked. Coronoid process of mandible erect, conical in profile, 

 the posterior outline with forward upward obliquity {Mustela^ 

 Putorius, — more nearly vertical in Gulo), the apex in advance 

 of the condyle. Feet with ordinary development and ratio of 



* It is curious to observe that au aquatic species of Futorius (P. vison, the 

 Mink) tends to approach the aquatic Otters (Lutrinw and Enhydrina') in the 

 relative shortness of rostrum, its less oblique truncation, tlatness on top, &c. 



tHere again the aquatic Paforius vison approaches the other aquatic 

 species of different subfamilies in the comparative liatuess of the bulUe. 



