24 THE NAUTILUS. 



the laboratory. As no other cases of conjugation were encoun- 

 tered it has not been possible to determine whether the penis 

 regenerates or not, though I am firmly convinced that it does. 

 Whether this act of mutilation invariably takes place is not 

 known, and the significance of the process is far more obscure. 

 It is possible the amputated penis may act as a plug to retain 

 the spermatozoa in the seminal receptacle, or on the other hand 

 it may be that the presence of a human observer or some natural 

 enemy brings with it unusual conditions, such as jarring the 

 earth or some specific scent, and that the severing of the intro- 

 mittent organ is a provision whereby the animals are enabled 

 to separate more rapidly than usual. The fate of the penis is 

 likewise unknown ; it evidently is either absorbed or, what is 

 more likely, is cast out before the eggs pass to the exterior. 



NOTES. 

 POLYGYRA ALBOLABRIS MAJOR AND P. A. FUSCOLABRIS. Clapp 



mentioned that you wanted to examine the animal of Polygyra 

 albolabris major Binn. I happened to have one. So send it. 

 The form ranges through Southern Alabama and I have found 

 it as far north as Wetumpka. In Central and Northern Ala- 

 bama the common large southern form of albolabris is pretty 

 generally distributed, though not very common : some speci- 

 mens approach major in size. 



' ' The form which you called P. albolabris fuscolabris is as far 

 as I know confined to the Cumberland Plateau and outlying 

 masses (Monte Sano etc. ) in Madison and part of Jackson Cos. 

 Judging by the shells alone, I should be very much inclined to 

 call this a distinct species. Ordinarily it is flatter than albolabris 

 and always it can be easily distinguished by its peculiar luster 

 as if varnished lightly : this is due to microscopic sculpture. 

 Some of our specimens are larger than the average major. By 

 the way, you must have had a specimen which was not quite 

 mature : in full-grown shells the lip is white and the body of 

 the shell is rather dark brown." HERBERT H. SMITH. 



Having dissected the specimen of P. a. major sent, I find it 

 identical with P. albolabris anatomically, and its status as a sub- 

 species rather than a distinct species is therefore confirmed. 



H. A. PILSBRY. 



