Descriptions of New Fluviatile Shells. 



the full grown ones. In Cany fork, I collected twelve hundred 

 specimens of Melania pernodosa, Lea., one hundred of M. alveare 

 Conrad, one hundred M. robulina Anthony, and some three or 

 four hundred of mixed species, in about one hour's search. I 

 found the specimens everywhere very much coated, generally 

 with ferruginous matter; but on one occasion, I found every 

 specimen in a small run, enveloped with a thick deposit of 

 calcareous matter, so that they looked like slender hazel nuts 

 the deposit being probably three or four times the weight of the 

 nucleus, the inclosed Melania. Not a particle of the shell was 

 visible, yet the animal within was alive, and apparently as well 

 circumstanced as a Melania ought to be. I found but few 

 Anculosce. Out of the Tennessee, Cumberland, Cany fork, Se- 

 quatchee, Holston, and other large streams visited, a few were 

 taken. They were particularly abundant in the Green Eiver 

 and the Sequatchee, two rapid, noisy, rocky streams, favorable 

 to that genus, which cannot bear a sluggish, muddy river at all. 

 I never found Anculosoe, even when abundant, save in the 

 most rapid current of a stream, where they cling to the stones 

 or rocks, generally in quite deep water. They cling to 

 these stones with no ordinary tenacity, and it requires some 

 exertion often to dislodge them. As one might suppose, their 

 peculiar fondness for the most rapid parts of the most rapid 

 rivers is not favorable to perfection of specimens ; and hence, 

 in this genus, the erosion of the apex forms, in most cases, a 

 conspicuous character. The lo seems to be closely allied to 

 the Anculosa in this respect, and inhabits deeper water. Geese 

 are said to devour the Melanice in great quantities, and often 

 to suffer from the abundance of such a diet. 



Should his life and strength be continued, the author hopes, 

 in due season, to furnish a complete monograph of the Me- 

 lanidae of the United States, in which an attempt will be 

 made to establish the true species, to rectify the nomenclature 

 of those regarded as erroneous, and to perfect such previous 

 descriptions as were founded on insufficient material. 



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