292 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



From the opening to the NW. edge of the slough is nearly 10 miles, 

 and at no point inside it do the soundings agree with those given on 

 either our own or the English charts, but a French chart shows some- 

 thing like this pocket. 



The slough is wider across the center than at the opening. The posi- 

 tion given is one determined by three persons, each of whom had his 

 own chronometer, and the three positions differed but little over half a 

 mile. The one given is the mean. 



There is a similar pocket off Sable Island, with the opening to the 

 southward, which is 5 miles across and in which soundings have been 

 found at a depth of 350 fathoms. 



This pocket is of the same character as the one described, but ouly 

 one position has been observed, which is latitude 43° 17' N., longitude 

 61° 8' W. There are several of these pockets on the Banks which are 

 known to the fishermen of Gloucester, as they go to them for halibut. 



Schooner Augusta H. Johnson, Gloucester, Mass., July, 1885. 



88.— THE PEARL FISHERIES OF TAHITI. 

 By ROUCHON-BRANDEI/r. 



[Abstract from Official Journal.] 



The author was sent by the Ministry of Marine and the Colonies on a 

 mission to Tahiti to study questions relating to oyster culture there. 

 The principal product of what Brandely, with " the summer isles of 

 Eden " fresh in his mind, calls " notre belle et sipoetique colqnie de Taiti " 

 is mother-of-pearl. All its trade is due solely to this article, which for 

 a century has regularly attracted vessels to the islands which compose 

 the archipelagoes of Tuamotu, Gam bier, and Tubai. The mother-of- 

 pearl which is employed in industry, and especially iu French industry, 

 is furnished by various kinds of shells, the most estimated, variegated, 

 and beautiful of which are those of the pearl-oyster. There are two kinds 

 of pearl-oysters ; 'one, known under the name of pintadine (Mcleagrina 

 margarittfera) is found in China, India, the Red Sea, the Comoro Islands, 

 Northeastern Australia, the Gulf of Mexico, and especially in the Tuam- 

 otu and Gambier archipelagoes ; the other, more commonly called the 

 pearl-oyster (JfeZe«#nna radiata), comes from India, the China Seas, the 

 Antilles, the Bed Sea, and Northern Australia. The shell of the former 

 is harder, more tiuted, more transparent, and reaches greater dimen- 

 sions than the latter. Some have been found which have measured 30 

 centimeters iu diameter and weighed more than 10 kilograms, while the 

 Mcleagrina radiata rarely exceeds 10 centimeters at the most, and never 

 Weighs as much as 150 grams. Both varieties supply pearls, those of 

 one kind being at one time more favored, at another time those Of the 

 other. This depends on fashion; but, on the whole, those found in the 



