STYLODONTID-E. 289 



Genus CHIRONECTES, Illiger 1 . 

 Mainly distinguished from DidelpJiys by the structure of the feet. 



Cfjirontcttd minimus (Zimmermann 2 ). 

 Syn. Lutra minima, Zimmermann 3 . 

 Chirontes variegatus, Illiger 4 . 



In two recent examples the length of the lower series of cheek- 

 teeth is 0,030 and 0,027, and that of the true molars 0,0185 and 

 0,016. 



Hob. Central and South America. 



18890 1. The left ramus of the mandible of a subadulfc individual, 

 showing the canine, p m . 3, m. 1, and m72 in use, and pra7~4 

 and m . 4 in alveolo, the crowns of the other teeth being 

 broken off; from a cave in Minas Geraes, Brazil. 



Claussen Collection. Purchased, 1845. 



GKNTTS non det. 



41995. The hinder half of the skeleton of a small Mammal, perhaps 

 belonging to the Didelphyidce, embedded in a slab of the 

 Montmartre gypsum.' The limb-bones are rather larger 

 than those of the type of Didelphys cuvieri. 



The affinities of the two following families require further elucidation. 



Family STYLODONTID^E. 



The following characters are found in the English genera : 

 Dentition (in the type genus) : I. J, C. | , Pm. \ , M. ? . The 

 hinder lower true molars form single cingulated cones ; the lower 

 premolars are laterally compressed; and the lower incisors are in 

 contact. In the upper dentition referred by Owen to the type genus 

 the true molars have narrow, triangular crowns 8 . The American 

 Jurassic form described by Marsh 6 under the name of Stylacodon, 

 and referred, with Stylodon, to his family Dryolestidce, appears to be 

 closely allied to, if not identical, with the latter ; Asthenodon (see 

 p. 273) is probably related. 



1 Prod. Syst. Mamm. et Avium, p. 76 (1811). 



3 Geogr. Qeschicht, vol. ii. p. 317 (1780). Lutra. 3 Loc. cit. 



* Abh. k. Ak. Wiss. Berlin, 1811, p. 107. 



5 There is considerable doubt as to the correctness of this reference and 

 the specimens may belong to another family. 



6 See Amer. Journ. ser. 3, vol. xxxiii. p. 334 (1837). 



PAKT V. U 



