255 



This process has the advantage over the one in which Chlorate of 

 Potassa is used, that the vapors evolved are neither deleterious to the 

 lungs nor explosive. Beside, in the change of color undergone on the 

 removal of organic matter, we have an easy method of ascertaining 

 when to stop the action of the chemicals used. 



Mr. Stodder said, in regard to the marks of Diatoms, that 

 Wenham some years ago stated that they are hexagonal, 

 while Prof. Rood, in the last number of Sillima^i^s Journal., 

 (Nov., 1861,) maintains that they are circular. He exhibited 

 some photographs sent him by the latter gentleman, in sup- 

 port of his position. Mr. Stodder was still of the opinion 

 that the marks are hexagonal. 



Ox Melania (Amxicola) Lapidaria. By James Lewis, of 

 Mohawk, N. Y. 



Some time ago I had some correspondence with Mr. W. G. Binney, 

 in which I called his attention to a small mollusk which is catalogued 

 in the Check Lists of the Smithsonian Institution as Amnicola lapida- 

 ria (Say), it having been described originally by Mr. Say as a Cy- 

 clostoma. 



There are some peculiarities in the liahits of this little mollusk which 

 are somewhat anomalous, and which, taken in connection with the 

 true generic characters which I have recently ascertained, prompt me 

 to present the following notes, which may be useful to other natural- 

 ists who have not had the same opportunities I have to examine the 

 soft parts of the animal. 



Melania lapidaria, (Lewis.) 

 Cyclostovia lapidaria, (Say.) 

 Amnicola lapidaria, (Binney,) in Sm. Catalogue. 



Soft parts identical in form with Melania. 



Foot short, broad anteriorly ; head proboscidiform ; eyes lateral, pro- 

 jecting, surrounded by an elevated process which is continued anteri- 

 orly to the base of a short and drooping tentacle. Mouth, foot, and 

 neck of a translucent slate color, which becomes blended with a deli- 

 cate reddish brown on the space between the eyes. Opercle, as in 

 Melania. 



Habits, evidently air-breathing.* Specimens in water seemed not 

 embarrassed in their movements, though they soon made their way 

 out, apparently preferring to be out of it. The drooping of the tenta- 

 cles is evidently caused by their adherence to the moist surface of the 



* Specimens dropped into water for the purpose of examining the soft parts gave 

 off numerous small bubbles of air. 



