MUSTELINE. 17 



inner tubercle is large and depressed, with a sharp raised edge. M. 1 is a largo, 

 somewhat irregular tooth, broader than long, with two cusps on the outer edge, 

 divided by a depression from two on the inner border. 



Permanent Dentition of the Lotrer Jaw. — I. 1 is very small; i. 2 and .3 are 

 slightly larger, but are very simple one-rooted teeth. The canine, as in the upper 

 jaw, is greatly larger than the in cisors. Pm. 2, 3 and 4 are simple, conical, two- 

 rooted teeth, the cone in pm. 2 being obliquely truncated in front. M. 1, the 

 carnassial, is a relatively large tooth, somewhat variable in character. The posterior 

 half, or talon, is depressed ; the anterior half bears two trenchant lobes, with a 

 large tubercle internal to the posterior lobe. The cingulum is prominent in m. 1 

 and all the lower premolars. M. 2 is a rather small square tooth, with a flattened 

 crown and a single root. 



c. The Vertebral Column. 

 The numbers of the vertebrae are as follows : 





Cervical. 



Thoracic. 



Lumbar. 



Sacral. 



Caudal. 



Mustela 



7 



14 



6 



3 



18—33 



Gulo 



7 



15 



5 



3 



14 or 15 



Metes . 



7 



15 



5 



3 



18 



Lutra 



7 



. 14—15 



. 5—6 . 



3 



25—26 



There is little in the vertebral column of the Mustelidas which demands special 

 comment, but allusion may be made to the following points : 



(1) The length of the tail in Lutra. 



(2) The relatively large size of the atlas vertebra in Lutra and Mustela. 



(3) The length of the spines of the anterior thoracic vertebras of Gulo. 



(4) The elongated character and shortness of the neural spines of the lumbar 

 and posterior thoracic vertebras of Mustela. 



(5) The expanded character of the transverse processes of the lumbar vertebras 

 of Lutra. 



d. The Limb Girdles. 



The Pectoral Girdle. — The scapula shows a considerable amount of variation in 

 shape and in the character of the acromion, which is always strongly developed, 

 while the coracoid process is scarcely defined. In Mustela, Gulo, and Lutra there 

 is a very large pre-scapular fossa and the coracoid border is gently curved. The 

 supra-scapular border in Gulo and Lutra forms an angle not much less than a right 

 angle with the spine. In Mustela the supra-scapular border is very short, and the 



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