84 



Warren's skeleton of the Mastodon, — the account of its disco- 

 very and disinterment being quite cleat. 



The Swan River scapulce belonged to an individual of inter- 

 mediate size, between the Cambridge (Massachusetts) Mastodon 

 and Dr. Warren's. 



The President observed that it would be very satisfactory, 

 if it could be well established that a depression exists in 

 the infra-spinal surface of the scapula of the Mastodon and 

 not in that of the Elephant. This he had found to be the 

 case with the Mastodons here, and on this account Sir John 

 Richardson transfers the Elephas Rupertianus to the Mas- 

 todon. 



Prof. Jeffries Wyman stated that the " Impression of a 

 doubtful sixth toe in some Batrachian footprints," spoken of 

 by President Hitchcock, might be explained by the presence 

 of a tubercle which exists upon the inside of the great toe 

 in this class of animals. Cuvier speaks of a tubercle in this 

 position supported by a single bone. Prof. Wyman has 

 seen in several skeletons, prepared by Mr. Fletcher of the 

 Scientific School of Cambridge, this tubercle supported by 

 a chain of three bones. It is doubtful if these bones are to 

 be considered as true phalanges ; they are more probably, 

 as Cuvier suggests with regard to the single bone, tarsal 

 bones out of place. 



Mr. Girard remarked that many Batrachians have two 

 tubercles, one on the great and one on the little toe, so that 

 two supernumerary impressions might in some instances be 

 made. 



The President exhibited a small slab from Turner's Falls, 

 bearing upon its upper surface ripple-marks of two different 

 characters, evidently made at different times, and impressions 

 of a doubtful nature. The President, in a late visit to the 

 Connecticut Valley, had obtained from Mr. Field many fine 



