MUSEUM OF COMPARATIVE ZOOLOGY. 9 
depths they fail to find them. Such, at least, has been the experience 
of Johannes Müller, Claparéde, and a host of others who have followed 
their methods of fishing either at the surface 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 trae 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 uscless 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 stool rope. 
We leave to-morrow to run a line of dredging from the Tortugas to 
the mouth of the Mississippi River. 
I am fortunate 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, 
