BULINUS. 487 



" Shell lietcrostroplie, pale yellowish, very fragile, diaphanous, 

 oblong ; whorls six or seven ; spire tapering, acute at tip ; 

 suture slightly impressed ; aperture not dilated, attenuated 

 above, about half as long as the shell ; columella much nar- 

 rowed near the base, so that the view may be partially ex- 

 tended from the base towards the apex." (^Say.) Length, 

 half an inch ; breadth, one fifth of an inch ; divergence, ^^^1^^- 

 thirty-four degrees. 



Found in stagnant waters in all the northern and western parts 

 of the United States. In the vicinity of Boston it is rare. 



Animal dusky, the head above of an orange hue ; tentacula rather 

 short and blunt, lighter at tip ; respiratory groove long, narrow, and 

 thin, movable in various directions, almost as long as a tentacle, 

 with two black spots like eyes near its tip. 



This species is easily recognized by its slender, elongated form, 

 and the great proportionate length of the spire. It is in every re- 

 spect similar to Physa hypnorum of Europe, unless, perhaps, its 

 spire may be somewhat more produced. 



It is not very common in Massachusetts, and is seldom found as 

 long as the above dimensions ; while Mr. Say gives it seven tenths 

 of an inch in Illinois. 



Mr. Say describes the animal as black, and spotless above and 

 below ; tentacula with a white ring at base. He must have observed 

 them at a more advanced age than any I have seen living ; or else 

 the species observed are different. 



The difference between this and Physa fontinalis of Europe is 

 very slight. The spire may l)e a little more prolonged and acute. 



It is quite interesting to keep a numl)er of them in a vessel of 

 water, and observe their motions and hal»its. The manner in which 

 they open their mouths and display the lingual organ, the manner in 

 which they rise to the surface and open the air cavity, into which 

 its structure permits no water to enter, and, above all, the Ijeautiful 

 and unaccountable manner in which it glides along, will never fail 

 to excite astonishment. They feed freely upon any kind of vegetable. 



We have here an instance of the intermina])le chain of existences, 

 and of the subserviency of one animal to another. And it is cu- 

 rious, too, that in general we have the power to elude or subdue 

 animals of greater strength and magnitude than ourselves, much 

 better than we can those which are inferior to us. On looking 

 carefully about the neck of the animal of this shell, we find him beset 

 with numerous little things looking like short, minute, white lines, 



