THE MUSEUM. 



•53 



discoveries from time to time in var- 

 ious parts of the United States, and 

 particularly in the Mississippi \'alley, 

 of pearls yielded by the fresh-water 

 bivalve shells (Unionida-) so abundant 

 in many of our inland waters, I was 

 invited in 1S94, to undertaka system- 

 atic inquiry for the United States 

 Commission of Fish and I-'isheries, to 

 ascertain, as far as possible, the facts 

 relating fo the occurrence and distri- 

 bution of the pearl-bearing species, 

 and the extent and conduct of the 

 pearl industry, as thus far de\eloped. 

 The value and elegance of many of 

 these pearls, especially as shown in 

 the exhibits made by the Columbian 

 Exposition in 1S95, the popular ex- 

 citement or "pearl fevers" at times 

 arising in districts where a few pearls 

 have been found and characterised by 

 wholesale and reckless destruction of 

 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 seems to call for a careful investi- 

 gation by the Commission, with a 

 view to better knowledge and wiser 

 direction in the matter of mland Amer- 

 ican 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 strifie for both 

 races, and not until the great water- 

 ways of the Mississippi Valley had 

 been won by the whites, the region 

 occupied and settled communities es- 

 tablished do we again begin to find 

 any indications of the search for fresh- 

 water pearls. For some two cen- 

 turies 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 concholo- 

 gists have paid attention to our native 

 pearls. It is probably accounted for 

 by the fact that the pearls are con- 

 tained 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 ob- 

 served a pearl of value. Pearls are 

 usually found either by farmers, who 

 devote their spare time to this indus- 

 try, and if no result is obtained suffer 

 no loss, or by persons in country vil- 

 lages who are without regular occupa- 

 tions, but are ever seeking means for 

 rapid increase of fortune. Multitudes 

 of shells that do not contain pearls are 

 destroyed in the search. 



HABIT.\T OF THE FRESH-WATER MUSSEL. 



From the many inquiries sent out 

 the general indications from these data 

 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, how- 

 ever, occur in muddy or clayey bot- 

 toms where the water is slower. The 

 preferences to rock bottom do not 

 concern so much the immediate sur- 

 face 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 allu- 

 sions to "hard" or calcareous water 

 tend to confirm the general impres- 

 sion that streams of this kind are fav- 

 orable to the development of mollus- 

 can shells, both in size and abund- 

 ance of calcareous matter in the water 

 tends to induce the prolific secretion 

 of the pearls. 



A Florida writer states that the 

 best Unio growth is found in lakes 

 with outlets, with water pure and 

 fresh, but adds that it is sometimes 



