ZOOLOGY. 331 







treme of size is found in the tropics, and the other in temperate cli- 

 mates, but that, while both appear in tropical countries, one extreme 

 is deficient in temperate regions. Within the tropics, however, there 

 appears to be a great difference in the average size of the land shells 

 of different regions. In the West Indies and the Polynesian Islands, 

 there is a great proportion of small species. But in Brazil and the 

 Philippine Islands, there are very few small land shells. It is re- 

 markable that this purely geographical difference greatly exceeds the 

 average difference in the species of different zones. 



CALIFORNIA PEARL FISHERIES. 



THE pearl fisheries on the western coast of Central America are at 

 present principally conducted by divers and vessels from Acapulco 

 and Mazatlan. The shell-fish producing the pearl, well known to be 

 of the genus Mi/a, species margaritifera, occurs abundantly in the 

 Gulf of California, adjoining both American and Mexican territory. 

 The pearls are of excellent water, or lucidness, but generally irregu- 

 lar in form. The vessels employed in the fishery are from 15 to 30 

 tons burden, and generally owned by individual adventurers, and com- 

 manded by them. There is on board of each ship a working crew of 

 sailors and an equal number of Indian divers, technically called Busos. 

 With meagre supplies, these vessels sail for the fishing-ground and at 

 once commence business. The Busos, armed with pointed staves, 

 plunge into water four or five fathoms deep, and when they find a 

 pearl-bearing oyster, rise to the surface and deposit their prize in a 

 sack hung to the vessel's side. This they continue to do until ex- 

 hausted, or their time of labor is over. When this is the case, all 

 collect around the owner or armador, who divides the gains in the fol- 

 lowing proportion, viz. two for the government, two for himself, and 

 one for the Buso. The share of the Buso is generally taken by the 

 armador, who contrives to keep in his debt for extra allowances, outfit, 

 etc., all his crew. Often when a Buso arrives at the surface of the 

 water, the largest oyster he has taken is laid aside for use of the Vir- 

 gin, and the simple-minded Indian rarely objects to this pious swindle. 

 In 1831, one vessel with seventy Busos, another with fifty, two with 

 thirty, and two with tea each, sailed from the coast of Sonora ; one 

 of these brought home in two months forty ounces of pearls, worth 

 $6,000; another, twenty-one ounces, worth $3,000, and the rest 

 proportionate quantities. Thus far, no attempts have been made by 

 the Americans to prosecute the pearl fishery, yet we doubt not that, 

 at no distant day, it will become an important and lucrative branch of 

 industry. 



REPORT ON ZOOPHYTES. 



Silliman's Journal for March, in a notice of Dana's " Report on 

 Zoophytes," states that the number of species of corals collected by 

 the Exploring Expedition was so large that it became necessary to 

 revise this department of science throughout, so that the volume in- 



