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On the supposed Garnivora of the Eocene of the Rocky Moun- 

 tains Animals which fulfilled the functions of the existing Gar- 

 nivora were abundant in North America during the Eocene period. 

 The Wahsatch beds of New Mexico have yielded remains of more 

 than a dozen species, which ranged from the size of a weasel to 

 that of a jaguar. Investigation into the structure of these shows 

 that while they differ in minor points among themselves, they 

 agree in possessing characters which distinguish them from the 

 true Garnivora. I have already pointed out, 1 that, in the genera 

 Ambloctonus, Oxysena, Stypolophus, and Didymictis, the tibio- 

 tarsal articulation differs from that of the existing Garnivora, and 

 suggested that these forms might prove to be gigantic Insec- 

 tivora. Further investigation has satisfied me that they cannot 

 be included in the order Garnivora, and their systematic position 

 proves to be of considerable interest. 



A greater or less part of the cranial chamber is preserved in 

 specimens of Oxysena forcipata and Stypolophus Mans. In these 

 animals it has a long, narrow form like that of the opossum, and 

 in the first named, where the interior form can be seen, it is evi- 

 dent that the cerebral hemispheres were small and narrow, and that 

 the olfactory lobes were relatively large, and were entirely un- 

 covered, projecting beyond the hemispheres. 



In Ambloctonus, Didymictis, and three undetermined forms, the 

 femur supports a third trochanter. In all the genera the ilium 

 has a well-marked external anterior ridge, which continues from 

 the acetabulum to the crest, distinct from the internal anterior 

 ridge. The ilium has, therefore, an angulate or convex external 

 face, as in Insectivora and Marsupialia, and does not display the 

 usual expansion in a single plane of most of the placentals. In 

 all the genera there is a strong tuberosity in the position of the 

 anterior inferior spine, which is wanting in the Mammalia, except- 

 ing certain Insectivora and Prosimise* although it marks the posi- 

 tion of the origin of the rectus femoris muscle in all types. 



The glenoid cavity of the squamosal bone is transverse, and 

 well defined anteriorly and posteriorly, as in the Garnivora. Of 

 the first series of carpal bones of the four genera named, I have 

 been able to learn nothing, but in the genus Synoplotherium from 

 the Bridger Eocene of Wyoming, which probably belongs to this 

 group, the scaphoid and lunar bones are separate and not united 

 as in the Garnivora. 



The above characters point to the Marsupialia or the Insec- 

 tivora as the proper location for the flesh-eaters under considera- 

 tion ; and the evidence is much more weighty in favor of the lat- 

 ter order as their true position. For in the genera Oxysena and 

 Didymictis the posterior part of the inferior border of the mandi- 

 bular ramus is not inflected as in Marsupialia, nor are the ante- 

 rior interior iliac tuberosity and third trochanter seen in that or- 

 der, while both exist in the Insectivora. 



Cuvier describes 3 the tibia of Garnivora as follows: "Quanta 



1 Systematic Catalogue of the Vertebrata of the Eocene of New Mexico, 

 1875, p. 7. 



2 See the figure of Solenodon by Peters, and Chiromys by Owen. 



3 Ossemens Fossiles, vii. p. 112. 



