1904.] Allen, Mammals from Santa Marta, Colombia. 453 



This species agrees with other South American otters in the 

 general form of the braincase, which is low, flat, and much 

 expanded, in comparison with the Lutra canadensis group of 

 North America, in which the braincase is much narrower, 

 deeper, and less expanded. The audital bullae are very small 

 and flat, the teeth large for the size of the skull and greatly 

 crowded in the tooth line. It differs from L. annectens For- 

 syth-Major (from Jalisco, Mexico), which also belongs to the 

 South American group, in its much smaller size and relatively 

 much larger teeth, particularly pm 3 and pm 4 . A specimen 

 of the latter from Laguna de Juanacatlan, Jalisco, Mexico 

 (practically a topotype), has a basal length of 112, a zygo- 

 matic breadth of 83, and a mastoid breadth of 76, while the 

 largest specimen of a series of four from Bonda has the corre- 

 sponding measurements, respectively, 101, 67, and 64.6. 



It is rather smaller even than L. insularis F. Cuvier, from 

 Trinidad, which has the braincase higher and more convex, 

 the audital bullae about one fourth larger, and the dentition 

 much weaker nearly one third less massive and the form 

 of pm 4 is strikingly different, the postero-internal basal por- 

 tion in insularis being very narrow, instead of very broad as 

 in L. colombiana. In short, L. insularis is a very strongly 

 differentiated insular type, sharply set off from the other 

 South American otters by strongly marked dental and cranial 

 characters. 



Unfortunately, no specimens of L. enudris (commonly 

 emended to enhydris) F. Cuvier, described from Guiana, are 

 available for examination. According to Forsyth-Major 

 (Zool. Anz., XX, 1897, p. 141; Ann. and Mag. Nat. Hist. (6), 

 XIX, 1897, p. 6 1 8), the audital bullae are less flattened than 

 in L. canadensis, but in L. colombiana they are very much 

 more flattened than in L. canadensis, in this respect agreeing 

 with L. insularis. In view of the several strongly marked 

 local forms now so well known in the L. canadensis group, 

 and the striking cranial differences that distinguish the Santa 

 Marta animal from its nearest known geographical allies - 

 the Mexican L. annectens on the one hand and the Trinidad 

 L. insularis on the other, and in view of the general fact 



