NATURAL SCIENCE'S OF PHILADELPHIA. 137 



edly co-state, usually with about six ribs, denticulating either 

 margin. 



Pallifera dorsalis, Binney. 



An opportunity has lately been given us by Mr. H. Prime of 

 examining living specimens from Westchester Co., New York. 

 We find Mr. Morse's description and figure of the jaw to be quite 

 correct, and have no doubt of the genus being distinct from 

 Tebennophorus. The species appears to us well marked also, 

 especially by the great activity of the animal's motions. 



Mr. Prime noticed it climbing on trees, a habit often observed 

 by us in several of our land shells. Thus Helix thyroides in 

 the garden of one of us at Burlington, N. J., constantly climbs 

 the fruit trees, to eat the gum which exudes from the branches. 



Our figure 535, of L. and Fr. W. Shells, part I., is defective. 

 The head does not extend beyond the mantle. See the upper 

 figure in Terrestrial Mollusks, III., pi. lxiii. 



10 



