Dr. Hildreth on fresh water Shells. 277 



and much admired by the lovers of shell fish at the present 

 day, particularly the Unio ellipticus, and Alasmodonta com- 

 planata, which are very large, and in the month of Septem- 

 ber abound in fat, to the extent of one or two ounces of clear 

 oil in a single individual. In the early settlement of this vi- 

 cinity, shells were much used for the manufacture of lime, 

 being burnt in piles of alternate strata of logs and shells ; 

 and affording an article of the greatest purity and whiteness. 

 They were in such abundance that a single individual could 

 collect twenty five or thirty bushels in a day — But at present, 

 I think they are less numerous, being destroyed in the low 

 stages of water by hogs, which become very fond of them and 

 will spend whole days in the water searching for their favor- 

 ite food ; many times preferring them to corn, which they 

 have been known to leave, and go in search of the more lus- 

 cious clam. They have also other harrasing enemies in the 

 Muskrats ; which collect vast heaps of shells at the mouths of 

 their favorite retreats, in the vicinity of some sunken log, on 

 which they sit and feast upon the choicest of the molluscous 

 race. It is also said that the white perch make use of the 

 more thin shelled varieties, for food ; being provided with 

 strong bony plates, thickly studded with smooth round teeth, 

 and placed in the back part of the fauces, well calculated to 

 perform the office of " nut crackers." The favorite haunts 

 of most of the genera are about the heads and sides of sand 

 bars and islands, where they can nestle in the sand and 

 coarse gravel ; other kinds prefer the rocky ripples, where 

 they can lie under the projecting edges of the loose stones ; 

 in the latter situations, are found most of the crested or win- 

 ged varieties, which probably accounts for the fact, that very- 

 few of the older subjects are found with crest perfect, but 

 generally mutilated and broken. As to their manner of 

 propagating the species, I have been able to learn but little 

 from my own observations, or by enquiries amongst fisher- 

 men, or others much about our rivers ; and except in one or 

 two varieties, have derived but little aid from writers on Con- 

 chology. From the fact, that the young from the size of a 

 pin head, to that of a pea, are found in great numbers in 

 the sand and soft ooze at the bottom of our streams, where 

 the water is still and calm, I am led to believe, that they are 

 male and female, and propagated by a seminal fluid, in the 

 manner of the finny tribe. But this is only a conjecture, 

 which further observations may confirm or refute. 



