THE MUSEUM. 



gathering cannot be carried on in win- 

 ter when the river is frozen, prices 

 rise in autumn. Several species are 

 capable of being used, of which two 

 are particularly mentioned, these are 

 "nigger head" shells, which have risen 

 with the approach of winter from 35 

 cents a hundred to 70 cents, and 

 "sand" shells have advanced corres- 

 pondingly from $1 to $2 per hundred. 



PRESENT ABUNDANCE OF THE FRESH- 

 WATER MUSSELS. 



Out of eighty-three papers which 

 respond to this inquiry seven describe 

 the shells as at present very abundant, 

 thirty-six as plentiful, twenty-five as 

 scarce, and three as absolutely exter- 

 minated, while twenty-eight papers 

 refer to the fact of diminish and di- 

 minishing numbers within a few years 

 past, some of them with great em- 

 phasis. The papers, Tennessee, Nos. 

 7, 32 and 33, estimate the present 

 number as reduced to one-tenth of 

 what they were ten years ago, and 

 over the same general fact is stated of 

 former abundance and present rarity, 

 and attributed to the pearl hunting 

 distraction of a few years past. Sev- 

 eral papers say that the shells are now 

 scarce in small streams and shallower 

 parts of large ones, while still abun- 

 dant in deeper water and where the 

 currents are strong. 



NATURAL ENEMIES. 



The response to question No. 7 in 

 eighty-four papers are varied and in- 

 teresting, and in some respects quite 

 contradictory. The chief natural 

 enemy of the Unios appears to be the 

 muskrat. Sixty-five papers refer to it, 

 twenty-six reporting large destruction 

 from this cause, thirty-eight in some 

 degree and one denying it. 



Hogs come next, and are referred 

 to in forty-seven papers. Of these 

 seven hold them responsible for large 

 destruction, thirty-five for some, or a 

 little, and five asserting that there is 

 none. Of other animals raccoons are 

 stated in thirteen papers to destroy 

 some shells;- mink in five, mud-turtles 



in three, crayfish in two, aquatic birds 

 in two, and cattle by trampling, in 

 three. All the animal depradators 

 deal only or chiefly with the Unios 

 that are either young, small-sized or 

 soft shelled, and hence not largely 

 pearl-bearing. The only exception to 

 this general rule is the statement in 

 one paper that many pearls have been 

 found where shells had been taken 

 ashore by muskrats and left to open 

 in the sun. 



INJURIES DUE TO PHYSICAL CAUSES. 



With regard to physical causes of 

 injury the most serious no doubt is 

 found in freshets. Of thirty-one 

 papers that refer to these, seventeen 

 report great destruction thereby, thir- 

 teen say "some" or "a little," and one 

 denies that there is any. Some pa- 

 pers say that their injury is small, and 

 that they only shift the beds and re- 

 distribute them, but a number describe 

 the burying of beds by the washing 

 down and caving in of the beds 

 in flood time, or the stranding of 

 great quantities of young shells to per- 

 ish when the water subsides. Two 

 papers that do not mention freshets 

 should doubtless be included here, 

 however, as they speak of destruction 

 caused to the shells by "covering with 

 mud" and by "change of bars V On 

 the other hand, low water and droughts 

 are reported as seriously harmful in 

 five papers, and drift-ice in three. 

 Two papers allude to disfiase as a 

 cause of injury and three to boring 

 parasites. 



EXTERMINATION OF THE MOLLUSKS. 



Question No. 28, as to exhaustion 

 of the mussel beds, its causes and its 

 rapidity, has called forth a very sug- 

 gestive body of replies in fifty-seven 

 papers. The remaining third makes 

 no response or none that is at all de- 

 finite. Nine papers report extermina- 

 tion of the shells, either actual or im- 

 minent, within a very few years past: 

 twenty speak of rapid diminution in 

 their nu- ■' rs; si:.'. :en of decrease as 

 noticed and progress, eight are uncer- 



