PROCEEDINGS 



OF THE 



ACADEMY OF NATURAL SCIENCES 



OF 



PHILADELPHIA. 



1875. 



January 5, 1875. 



The President, Dr. Ruschenberger, in the chair. 



Twenty-two members present. 



The following papers were presented for publication : 

 " On the Lingual Dentition and Genitalia of Partula and other 

 Pulmonata." By Wm. G. Binney. 



" On the Jaw and Lingual Membrane of North American Ter- 

 restrial Pulmonata." By Wm. G. Binney. 



On the Transition Beds of the Saskatchewan District. Prof. 

 Cope communicated the results of an examination of a series of 

 vertebrate fossils collected near the Milk River by George M. 

 Dawson, geologist of the British North American Boundarv Com- 

 mission. These were derived from beds of the Fort Union Epoch, 

 from a horizon one and two hundred feet above the beds of creta- 

 ceous No. 5. They embrace eight species of reptiles which are 

 determinable from the specimens, representing the two orders 

 Dinosauria and Testudinata. The specimens are the following: 

 Dinosauria, Gionodon stenopsis, sp. nov. ; ?Had?'osaurus, sp. (with 

 the candal vertebra slightly opisthocoelian) ; Compsemys ?victus, 

 Leidy; Compsemys ogmms, sp. nov.; Plastomenus coalescens, sp. 

 nov.; Plastomenus costatus, sp. nov. ; Trionyx ?sp., and Trionyx 

 vagans. The species marked with question are represented by 

 2 



