434 Bulletin American Museum of Natural History. [Vol. XXXV, 



company is t50 and the annual yield of shell 175 to 200 tons. The schooners 

 with their boats are divided into three fleets, the divers of each fleet using 

 their schooner as the home base. Pearl fishing is carried on at depths vary- 

 ing from 20 to 120 feet. 



A concession for pearl fishing around the islands of Espiritu Santo, San 

 Jose and Ceralbo in the Gulf, and also in Charmela Bay, sixty miles north 

 of Manzanillo in the Pacific, is held by Senor Miguel Cornego of La Paz. 

 With him is associated Senor Gaston J. Vives, in the management of the 

 "Compania Criadora de Concha y Perl a de la Baja California," engaged in 

 the propagation of the pearl oyster. The concession for oyster cultivation 

 dates from 1903. 



During the years 1910 and 1911 the total amount of shell exported from 

 La Paz and derived from the waters adjacent to the Peninsula of Lower 

 California was 331 tons. The industry has suffered considerably as a result 

 of disturbed political conditions in Mexico. 



The above figures relate to pearl shell only, and do not include the value 

 of pearls, which is reported to amount to about $100,000 annually. 



Pearl Oyster Cultivation. — An important feature of the pearl fishery of 

 La Paz is a station for the cultivation of the pearl oyster under the manage- 

 ment of Senor Gaston Vives. This station is located at San Gabriel Cove, 

 Espiritu Santo Island, in the Gulf of California, fifteen miles from La Paz 

 and is the only establishment of the kind in the world. 



The station has the appearance of being well adapted for the purpose for 

 which it was constructed. A great deal of space is occupied by the equip- 

 ment of the station and there is evidence that a considerable amount of 

 money has been carefully invested in the enterprise. The sub-station of 

 La Gallina on the opposite side of the cove, we had no opportunity to visit. 



The methods of pearl oyster culture practised here include the collecting 

 of young spat or seed in the open bay in artificial collectors, the transferring 

 of this seed to an artificial canal to which the tide is admitted and where 

 they are protected from their enemies by wire-screened gates, and finally, 

 after a period of growth and protection, a transferrence back to the natural 

 bottom in the open bay, in protected crates until mature growth is attained. 



The lagoon at San Gabriel has been cut off from the bay by a heavy 

 barrier of masonry, behind which has been constructed a long zig-zag canal 

 •of masonry for the protection of the immature crop of shells. This, the 

 so-called hatchery, is the place of growth for young shells obtained from the 

 spat collectors in the bay outside. The numerous cross sections of the 

 canal afford ample space for the operations of oyster cultivation and have a 

 uniform depth of seven or eight feet. 



The entrance is well screened to exclude mollusk-eating fishes, star- 



