324 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
sale and reckless destruction of the shells over large areas; the total lack of system 
in the search for pearls, as contrasted with the methods that have been developed on 
a smaller but far more profitable scale in Europe, all seemed to call for a careful 
investigation by the Commission, with a view to better knowledge and wiser direction 
in the matter of inland American pearl fisheries. 
Undoubtedly, for a considerable period after the first explorations, the pearl 
resources of North America seem to have attracted little attention. The Indian race 
was contending with the whites for the possession of the country; it was a time of 
uncertainty and strife for both races; and not until the great waterways of the 
Mississippi Valley had been won by the whites, the region occupied, and settled com- 
munities established, do we again begin to find any indications of the search for fresh- 
water pearls. For some two centuries the Unios lived and multiplied in the rivers 
and streams unmolested by either the native tribes that had used them for food, or 
the pioneers of the new race that had not yet learned of their hidden treasures of 
pearl. 
It is with some surprise that one notes that so few American conchologists have 
paid attention to our native pearls. It is probably accounted for by the fact that the 
pearls are contained in old, distorted, and diseased shells, which are not so desirable 
for collections as the finer specimens. Collectors who have opened many thousands 
of Unios have never observed a pearl of value. Pearls are usually found either by 
farmers, who devote their spare time to this industry, and if no result is obtained 
suffer no loss, or by persons in country villages who are without regular occupation, 
but are ever seeking means for rapid increase of fortune. Multitudes of shells that 
do not contain pearls are destroyed in the search. 
HABITAT OF THE FRESH-WATER MUSSELS. 
From the many inquiries sent out, the general indications from the answers are 
quite plain, to the effect that the shells are chiefly found in rather rapid streams, in 
which the bottom would naturally be sandy or gravelly and the water clear. Other 
species, however, occur on muddy or clayey bottoms, where the current is slower. 
The references to rock bottom do not concern so much the immediate surface where 
the shells are found, as the underlying bed on which the softer materials rest. 
In the matter of depth, also, the large preponderance of answers in favor of shallow 
streams may mean, not so much that the Unios greatly prefer shallow water, as that 
they are more readily found and gathered there. The frequent allusions to “hard” 
or calcareous water seem to confirm the general impression that streams of this kind 
are favorable to the development of molluscan shells, both in size and iu abundance, 
and the greater proportion of calcareous matter in the water tends to induce the 
prolific secretion of the pearls. 
A Florida writer states that the best Onio growth is found in lakes with outlets, 
the water pure and fresh ; but adds that it is sometimes sulphurous. A Texas pearler 
(Colorado, Concho, San Saba, and Llano rivers) refers to the water as becoming 
slightly alkaline in dry times; and another Texas- pearler (Colorado and Llano) makes 
a similar statement. A New York pearler (De Grasse Eiver and Plum Brook) men- 
tions the water as brown or black — the clear, brown water of the hemlock districts, 
familiar in northern New York. 
The general conclusions most clearly brought out may perhaps be summed up 
as follows: The shells are most abundant in swift and clear water where the bottom 
