PEARLS AND PEARL SHELLS. 457 



CULTIVATION OF THE PEARL OYSTER. 



In the Japanese section, K. Mikiinoto, of Toba, Shiina, Japan, made a remarkably 

 interesting exhibit of pearl shells from the Bay of Ago, province of Shima, on the 

 Pacific coast of central Japan, near the famous temple of ise. The Bay of Ago is 

 about 3 miles long and 2 miles broad, and, penetrating inland for some distance, its 

 waters are always calm. The pearl oyster is abundant along its shores at a depth of 

 from 1 to 6 fathoms, where the bottom is sandy, with a scant growth of seaweeds. 



Little can be ascertained as to when the fishing of pearl oysters began in this bay. 

 It is believed, however, to have commenced some three or four centuries ago. 



In about 1880, pearl fishing in this bay was very actively carried on, and although 

 pearls were comparatively cheap at that time, the annual yield amounted to $10,000. 

 But too great an activity on the part of fishermen led to a depletion of the fisheries, 

 so that the yield gradually decreased until in 1885 the value of pearls obtained was 

 less than $1,000. 



Fearing the extinction of this valuable shellfish, the Fisheries Association of the 

 district took steps to restore the industry by establishing a closed season, etc., and, 

 at the advice of the late Admiral Y. Yanagi, president of the Japan Fisheries Society, 

 of Profs. K. Mitsukuri and C. Saraki, of the Imperial University, and of Kishinouye, 

 the zoologist of the department of agriculture and commerce, tried with success the 

 experiment of collecting and rearing the spat on tiles, stones, logs, ropes, etc. By 

 the adoption of these various means the fishery has largely recovered its lost ground, 

 and for the past two or three years the yield of pearls has been restored to the amount 

 obtained at the active period of the industry. Mr. Mikimoto entertains every hope 

 of greatly extending and promoting the industry in the future by systematic cultiva- 

 tion of this kind. 



The chief source of pearls in Japan is the pearl oyster (Avicula martensii), but 

 the mussel (Mytilus crassitesta), the oyster, the sea-ear or abalone {Haliotis gigantea), 

 and the fresh-water pearl mussel (Dipsas plicatus) also produce their special pearls. 

 In Japan, as in Europe, pearls from the pearl oyster are especially valued on account 

 of their brilliant luster and pure color. Those with the silvery hue command higher 

 prices than those of the golden hue. Pearls from the mussel, the pearl mussel, etc., are 

 of various tints: those from the oyster are usually milky- white; while those from the 

 sea-ear (Haliotis) and abalone shell have usually a golden tinge. 



Mr. Mikimoto's exhibit illustrated the growth of pearl shells from one to nine years. 

 This shellfish spawns from June to August; therefore some of the shells exhibited 

 could not have been more than a few weeks old. These continue to grow until the 

 following November, when the approach of the cold season checks them for a time. 

 In March of the year following, growth again commences, and on this account Febru- 

 ary is considered the end of the "pearl-oyster year." In other words, young shells 

 collected in the first season, up to and including the following February, are called 

 first-year shells; those obtained from March of the second year to February of the 

 third year are known as second-year shells, etc. 



Note.— Articles figured on plates 29, 30, 32, 33, 34, 35, 36, 37, 39 (see page 440) are in the Tiffany- 

 Higinbotham Collection in the Field Columbian Museum, Chicago, Illinois. 



