MUSEUM OF COMPARATIVE ZOOLOGY. 193 



The surface at this point was also examined with the tow-net, and the 

 pelagic animals found to be the same as those brought up in the open 

 part of the tow-net on its way from the bottom. The number both of 

 species and specimens was, however, much less than in the Tanner net. 

 On the following day the Tanner tow-net was sent to be towed at a 

 depth of 214. fathoms. In twenty minutes the messenger was sent down 

 and the net hauled up. The bottom part of the net came up tightly 

 closed. Its contents were examined in the same manner as before in well 

 sifted water, and the water was found to be absolutely barren, while the 

 upper part of the net, which came up open, and was not more than eight 

 or nine minutes on the way, was well filled with surface life. The net 

 contained this time a number of Hyalceas and Criseis, in addition to 

 the things collected the day before. An examination of the surface fauna 

 at this same point with the tow-net showed the presence only in smaller 

 numbers of the same species which the open part of the same net con- 

 tained, except that there were a larger number of bells and fragments of 

 Diphyes and of Cristalloides than in the Tanner net. The point at 

 which this experiment was made was about 250 miles from the Galapa- 

 gos, and about the same distance from Cape San Francisco. There 

 were myriads of Nautilograpsus swarming on the surface of the water; 

 they literally filled the surface tow-net. On two other occasions, once 

 at a distance of 350 miles in a southeasterly direction from Aeapulco 

 (depth 2,232 fathoms), we tried the same experiment with the Tan- 

 ner net, and invariably with the same result. The net was towed at 

 a depth of 100, of 200, and of 300 fathoms, each time for twenty 

 minutes, the messenger sent down, and the bottom part closed. At the 

 depth of 100 fathoms, the closed part of the net contained practically the 

 same tilings as the open part of the net ; at 200 fathoms, the lower 

 part of the net contained but few specimens of the surface life ; and 

 at 300 fathoms, the closed bottom net came up empty. 



On the following day the surface was carefully examined, and the tow- 

 net sent to 175 fathoms, where it was towed for twenty minutes, and the 

 messenger sent down to close it. The lower net came up well filled with 

 the surface pelagic species, which on this day were unusually varied, 

 it having been smooth and calm the previous night, and the morning 

 before the towing was made. This haul was made in the evening, at, 

 8 p.m. The previous hauls had been made at about 10 a. m., in a bril- 

 liant sunlight. Again on the 11th of April, about thirty miles southeast 

 of Aeapulco, in a depth of over 1,800 fathoms, the Tanner net was sent 

 to a depth of 300 fathoms, and the messenger sent down to close it. 



VOL. XXI — NO 4. 13 



