LDTRA 355 



1865. Lutrogale Gray, Proc. Zool. Soc. London, p. 127 (Lutra monticola 



Hodgson). 

 1865. Nutria Gray, Proo. Zool. Soo. London, p. 128 (Lutra felina Molina). 

 1867. Lutronectes Gray, Proo. Zool. Soc. London, p. 180 (L. whiteleyi 



Gray = L. lutra Linnseus ?). 



Type species. — Lutra * Brisson = Mustela lutra Linnaeus. 



Geographical distribution. — Same as that of the sub-family. 



Characters. — Skull broad and low (depth of brain-case only 

 about half mastoid breadth), the entire dorsal profile nearly 

 straight, the zygomatic arches so widely expanded and post- 

 orbital region so much narrowed that distance from point of 

 greatest narrowing to zygoma is greater than postorbital con- 

 striction ; rostrum so shortened that posterior border of narial 

 opening approaches level of anterior zygomatic root, and distance 

 from orbit to gnathion is much less than half length of brain- 

 case ; auditory bulla flattened, with conspicuous meatal tube ; 

 paroccipital process low and ridge-like but distinct from bulla ; 

 dental formula : i ||, c £?, pm g, m £? = 36 ; teeth large as com- 

 pared with width of rostrum and palate (greatest transverse 

 diameter of upper carnassial equal to half distance between 

 carnassials) ; all of the small premolars opposed and capable of 

 trenchant action with those of opposite jaw ; upper carnassial 

 with crown triangular in outline, the outer side occupied by a 

 moderately high cutting edge formed by two cusps and a con- 

 necting ridge, the inner side (about half the total crown area) 

 by a flat crushing surface ; upper molar rhombic in outline, its 

 crown area about equal to that of carnassial (usually somewhat 

 smaller), its greatest diameter transverse to axis of tooth-row, 

 the four primitive cusps present ; lower carnassial with three 

 anterior cusps well developed, sub-equal, the posterior heel 

 slightly larger than anterior triangle ; external form highly 

 modified for aquatic life, the body long and of approximately the 

 same width as neck and head, the tail long, very muscular, broad 

 at base, tapering distally, the legs short, feet broad, toes webbed, 

 short-clawed, the fur soft, dense and impervious to water. 



Bemarks. — Although more widely distributed than any other 

 living genus of land mammals, Eptesicus and Myotis perhaps 

 excepted, Lutra is not rich in species. A dozen or fifteen forms 

 are currently recognized, only one of which occurs in Europe. 



LUTRA LUTRA Linnaeus. 



1758. [Mustela] lutra Linnseus, Syst. Nat., i, 10th ed., p. 45 (Sweden). 

 1777. [Lutra'] vulgaris Erxleben, Syst. Regni Anim.,i, p. 448 (Renaming of 



lutra). 

 1792. M[ustela] Lutra giscatoria Kerr, Anim. Kingd., p. 172 (Renaming of 



lutra). \i 



Not " Lutra lutra" (see footnote under Meles, p. 341). 



2 A 2 



