102 PROCEEDINGS OF THE ACADEMY OP 



of the animal; when within a few rods of the place, the almost 

 deafening noise that greeted his ears, from the tall trees, led him 

 to suspect that all was not right. After reaching the spot, a few 

 moments of anxious waiting sufUced to reveal to him the cause 

 of the noise and the origin of the sacrifice above alluded to; for, 

 sitting u[)on a twig just over his head, he observed a chickaree, 

 holding in its paws a bird which it had captured, and from Avhich 

 it was very contentedly sucking the life current. 



It is a well-established fact, lie furtlier remarked, as fiir as he 

 had been able to verify it, that the numerous species of Rodents, 

 with but two exceptions at tiie most, subsist principally or entirelj'' 

 upon vegetable matter, especially the hard parts of plants, such 

 as nuts, bark, and roots. 



Tills habit of imitating the propensities of the Mustelidae, he 

 thought might have arisen from the habit which some squirrels 

 possess, possibly the one under consideration, of sucking the eggs 

 of birds; the blood-sucking habit, he assumed to be an outgrowth 

 from the other. 



This adoption of another's mode of life by S. hudsonius, he 

 thought a discovery of some note, as usurpation of habits, lead- 

 ing to functional and structural changes in an animal's economy, 

 is accounted an element of no mean weight in the development 

 hypothesis, according to the testimony of able writers upon 

 Evolution. 



Prof. Cope exhibited the cranium of the horned Proboscidian 

 of Wyoming, Lo.volophodon cortmtiis^ and made some remarks on 

 its aflinities. The short-footed Ungulates or Proboscidia. are re- 

 presented by two very different families in the Eocene formations 

 of North America, the Eohasiliidse and Bathmodontidse. The first 

 embraces four known genera, as follows: 



1. Nasal bones with flat horizontal horn-cores ovei'hanging their 

 apex. 



Cervical vertebrae short; malar bone much reduced in front. 



Loxolophodon. 



2. Nasal bones with small tuberosities. 



Cervical vertebrae short. Eobasileus. 



Cervical vertebrae longer; the malar bone reaching maxillary 



face. Uintatherium. 



3. Nasal bones without the anterior horn-cores. 



Cervicals ? Megaceratops. 



Of the above genera there are five well-determined species, viz.: 

 L. cornutus, Cope; B. pressico7'nis^ Cope; U. 7'obuslu)n, Leidy; 

 U. lacustre, Marsh ; and il/. color adoensis, Leidy. E. furcatus, 

 Cope, and U. mirabile, Marsh, would, porha])S, have to be added. 



There are two genera of Bathmodonlidoc, as follows: 



One posterior molar with two transverse crests. Baihmodon. 



Three posterior cross-crested molars. Metalophodon. 



