Insectivora. — llammalia with small cerebral hemispheres which 

 do not cover the olfactory lobes, nor the cerebellum ; with numer- 

 ous clawed digits, and a third trochanter of the femur ; with a 

 transverse glenoid cavity for the mandible. 



Superior incisors normal, not growing from persistent pulps; 

 canines large ; premolars compressed. Astragalus not grooved 

 above, articulating with the cuboid as well as the navicular ; five 

 toes on the hind foot ; Greodonta. 



Superior incisors large, growing from persistent piilps, and 

 without enamel on the sides ; superior canines small when present ; 

 premolars wide or tubercular; Tillodonta. 



These suborders of the order Insectivora do not differ among 

 themselves more than do those of the Marsupialia, and constitute 

 a series of parallels with them. Thus the Greodonta resemble the 

 Sarcophaga, the Insectivora vera the Entomophaga, and the Tillo- 

 donta the Rhizophaga, typified by Phascolomys. 



The genera of the Greodonta differ as follows : — 



I. First and third inferior true molars without internal cusp. 

 Last superior molar longitudinal ; last inferior molar carnassial ; 



Ambloctonus. 



II. Inferior carnassials with interior tubercle ; no tubercular 

 molar ; last superior molar transverse. 



Three tubercular carnassials; 1 Stypolophus. 



Two tubercular carnassials ; Oxysena. 



III. Inferior carnassial with interior tubercle ; a tubercular 

 molar. 



One tubercular carnassial ; Didymictis. 



The number of toes on the hind foot cannot be certainly stated 

 in all the genera, but in Stypolophus Mans and another species 

 there were probably five, the inner being of reduced size. There 

 is present in those species an ento-cuneiform bone which resem- 

 bles that of Canis; it is compressed, with one truncate concave 

 terminal facet, and an internal oblique one at the opposite and 

 proximal extremity. The form of the truncate articular face of 

 the distal end indicates the existence of an inner metatarsal bone 

 of moderate proportions, which probably supported a small hallux. 

 This thumb could not be opposable as in the opossum. 



In general appearance the Greodonta differed from the Carnivora, 

 in many of the species at least, in the small relative size of the 

 limbs as compared with that of the head, and in some instances, 

 as compared with the size of the hind feet. The feet were probably 

 plantigrade, and the posterior ones capable of some degree of 

 rotation. The probable large size of the rectus femoris muscle 

 indicates unusual power^of extension of the hind limb. They were 

 furnished with a long and large tail. Probably some of the species 

 resembled in proportions the My thorny s and Solenodon, now exist- 

 ing in Africa and the West Indies, but they mostly attained a much 

 larger size. Published December 22, 1875. 



1 For the meaning of these expressions, see Syst. Cat. Eoc, New Mexico, 

 1875, p. 6. 





