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94 Scraps in Natural History. 



Physm. — Capturing some of the Physa heterostropha while 

 floating on the surface of a brook, I placed them in a bowl of 

 water, and entertained myself with their nautical skill, as they 

 directed their devious course over the fluid. The mouth of the 

 shell is turned upward, and by visible undulations of the mol- 

 luscan portion, which scarcely protrudes beyond the lip of the 

 shell, an easy, gliding motion is communicated to the calcareous 

 vessel. 



Shells abovt Richmond, Wayne County, Indiana. 



To know the barrenness of a locality in reference to geograph- 

 ical distribution is as desirable to the naturalist as the knowledge 

 of the fruitfulness of another district. And to trace to their 

 proper inviting and repelling causes the presence or absence of 

 objects of natural history in any given territory, is an interesting 

 item in his labors. To this end local catalogues, accompanied 

 with appropriate sketches of the district in question, may be ac- 

 cumulated with advantage in the literary repositories of science. 

 And more especially has it appeared to me to be desirable that 

 lists of the reptiles, insects, fishes, plants, &c. of newly settled 

 sections of the country should be made out, not only for present 

 purposes, but for the future student of nature who may traverse 

 the same regions when highly populated and improved, and the 

 influence of terrestrial cultivation on wild organic nature be de- 

 termined. Impressed with this view, I have for years past di- 

 rected my attention to the animal and vegetable kingdoms around 

 me, and have been endeavoring to perfect catalogues of their 

 several subjects. A list of our mammals, and a sketch of our 

 geography and geology, have already been published in this 

 Journal. I now transmit the names of such molluscs, terrestrial 

 and fluviatile, as I have been able to find. The catalogue it 

 will be perceived is not copious; the total absence of Unios is 

 perhaps attributable to the want of larger streams than our dis- 

 trict furnishes; and the absence of some others may be owing 

 to the newness of the country, and to the examination being 

 confined to a single observer. The nearest approximation of the 

 genus Unio that I have been advised of, is about twenty miles 



south of Richmond, whence I obtained a fine U. Cardium. 



