676 



4230. The os penis of a Polecat or Ferret. Mus. Urit. 



4231. The skull of the Mink (Putorius Lutreold). 



Presented by Henry Cline, Esq. 



Genus Mephitis. 



Dental formula : i g, e j^-J, p gj, m ^=34 . 



4232. The skull of the American Skunk (Mephitis americanus). 



The occipital condyles are separated by an interspace below. All the sutures of the skull 

 are obliterated. The tympanic bullee are very feebly developed. 



Presented by Henry Cline, Esq. 

 Genus Lutra. 



Dental formula : i jg, c |, p g, m =36. 



4233. The skeleton of an Otter (Lutra vulgaris). 



The vertebral formula is : 7 cervical, 14 dorsal, 6 lumbar, 3 sacral : there are 23 caudal, 

 but the series is incomplete. Ten pairs of ribs directly join the sternum, which consists of 

 nine bones and an ensiform cartilage. The spiue of the eleventh dorsal vertebra is vertical, 

 and those before and behind it converge towards it, as the centre of motion of the trunk. 

 The metapophyses begin to be developed on the twelfth dorsal vertebra, and are continued 

 throughout the lumbar series ; they are low and obtuse. The anapophyses commence at the 

 eleventh vertebra, and are continued to the penultimate lumbar. The spines of the three 

 sacral vertebrae have coalesced to form a vertical crista. Haemapophyses are developed be- 

 iieath several of the anterior caudal vertebrae ; they are articulated, and some of them become 

 anchylosed to short hypapophyses or exogenous processes from the under and fore part of 

 the centrum, and then are continued in several of the succeeding vertebras, which have not 

 the haemal arch complete. The neural arch is incomplete beyond the eighth caudal ver- 

 tebra. The entire tail is longer and much stronger than in the terrestrial Mustelidce : it is 

 the chief organ hi regulating the course of the Otter through the water. 



Presented by William Yarrell, Esq., F.L.S. 



4234. The skeleton of a male Otter (Lutra vulgaris). 



In this skeleton four vertebrae are anchylosed to form the sacrum, and there are 25 caudal 

 vertebrae, the two terminal ones being here present which are wanting in the preceding skele- 

 ton. The formula of the true vertebrae is the same. 



Mus. South. 



