MUSEUM OF COMPARATIVE ZOOLOGY. 9 



depths they fail to find them. Sucli, at least, has been the experience 

 of Johannes Miillcr, Claparede, and a host of others who have followed 

 their methods of fishing either at the surftxee or a little below it. The 

 specimens brought up by the "Challenger" from intermediate depths are 

 inconclusive, since the nets used were the ordinary tow-nets, which were 

 sent down open, kept open while towing, and remained open while coming 

 up. It is perfectly true that by differentiation of the contents of the 

 several nets at one locality some approximate results might be obtained, 

 if the work were carried on for a long period, but an occasional haul 

 taken by itself means nothing. For this reason, our time having been 

 already so far curtailed, it seemed useless to devote any portion of the 

 pleasant weather suitable for dredging to carry on work which at best 

 would only accumulate very indifferent evidence. We have, however, 

 attempted to devise a tow-net which will go down closed to any depth 

 required, will then open and tow while the ship is in motion, and close 

 again within a reasonable distance as it comes up. But thus far the 

 experiment has not succeeded. 



The number of casts made with dredge and trawl are over fifty, from 

 300 fathoms to 1,920 fathoms ; of these forty-three were successful hauls. 

 In making them we have thus far only lost 200 fathoms of steel rope. 



We leave to-morrow to run a line of dredging from the Tortugas to 

 the mouth of the Mississippi River. 



I am fortimate in having on this expedition, as on former collecting 

 excursions, the valuable and faithful assistance of Mr. Garman. Be- 

 yond this, whatever share of success has attended this winter's work 

 is due to the untiring energy of Captain Sigsbee. The interest taken 

 not only by him, but by all the officers and men of the " Blake," has 

 not flagged for an instant, day or night, as the amount of work accom- 

 plished during the comparatively short time of good weather amply 

 testifies. 



Alexander Agassiz. 



Key West, Feb. 27, 1878. 



