90 THE NAUTILUS. 



were obtained, has been examined as to its method of progression, 

 Figure 4. It is that of the ordinary snail, the under side of the foot 

 being in total contact with the surface over which it moves. Observed 

 from the under side when the animal is actively crawling over a sur- 

 face of glass, the foot is seen to be extended to a length of 20 mm., or, 

 including the labial tentacles and head segment, 24 mm.; the tentacles 

 may be protruded about 8 mm. more. The foot proper shows a central 

 muscular portion extending its entire length, about 3 mm. wide ante- 

 riorly and tapering to less than 1 mm. wide posteriorly; it is bounded 

 for its entire length on each side by an area that corresponds to the 

 edge of the foot on which the above operculates move. This has 

 apparently the structure of the upper surface of the foot and is not 

 involved in the muscular contractions during locomotion; it does not 

 appear to be traversed by the contractile muscles. When the under 

 side of the foot is observed during active motion of the animal, the 

 middle band of the foot is seen to contract in a series of waves which 

 traverse the length of the foot in about 10 seconds, or at a rate of 2 

 mm. per second. These waves follow each other closely; there are 

 about 50 to GO waves per minute. They move from the anterior to 

 the posterior end of the foot, in the reverse direction of the wave 

 movement described above for the other species. The foot is not so 

 firm as in the above species, and while the operculum is placed under 

 the shell it does not support it, as in the case of Coloboslylus, Tudora 

 and Adamsiella. The motion is perfectly even, rather slow, and of 

 course there is no swaying of the shell from side to side which is so 

 characteristic of the other species described. 



The movement of Stoastoma pisum (C. B. Ad.) resembles that of 

 the above species of Colobusty/us, Tudora, etc., and it has undoubtedly 

 been observed (though not, described), for Chitty gives a figure of 

 this species crawling which shows plainly the raised margin of the 

 foot, due to the passage of the wave. The figure is unaccompanied 

 by any description of this character of the animal. 



NOTES ON SOME LAND SNAILS FROM KENTUCKY. 



BY V. STERKI. 



On September 25th hist I had a few hours to look for snails at 

 Mnysville, Mason Co., Ky., in the Ohio Valley. The place was the 

 steep northeast slope of a limestone hill and on its top, for the most 



