20 Genitalia and Lingual 



Across Pond's Hollow, the limestone rests upon a sand- 

 stone, in its normal condition. 



All these changes take place in the distance of five miles. 



We have here the evidence of the following series of con- 

 ditions ; — first, two miles of strong currents, bringing in 

 coarse gravel ; next, gentler currents for one mile, bringing 

 in fine sand ; then a quiet bayou, a mile broad, receiving 

 deposits of carbonaceous mud ; then for another mile, 

 stronger currents again, carrying sands and pebbles ; and 

 finally at the Rockcastle River, tearing up the limestone and 

 giving instead of it a mixed deposit of lime, sands and peb- 

 bles. All these changes, looking at them with reference to 

 the coal above, are in one common horizon. 



IV. — On the Genitalia and Lingual Dentition of Pulmonala. 



By W. G. BINNEY. 



With Plates I-VI. 



Read May 25th, 1874. 



It will be noticed that in the following descriptions of the 

 genital system, I have followed Dr. Leidy (Terr. Moll. U. 

 S., I) in applying the terms ovary and oviduct. I am aware 

 of other names being applied to the organs by other authors. 



I take this opportunity of strongly urging upon concholo- 

 gists the study of the genital system as a most reliable spe- 

 cific character, in the terrestrial Pulmonata. 



For the species extralimital to the United States, I am 

 indebted to my friend, Mr. Thomas Bland, as well as for their 

 identification. The most interesting of them were collected 

 by Prof. Orton, in his late journey in northern Pern. 



Limax flavus, Linn. 

 A few days since a colony of this species was discovered 

 by a friend in the cellar of his house in Burlington, N. J. 



