XX INTRODUCTION. 
Gulf. Stream, to a distance of about 120 miles to the eastward 
of Charleston. Finding that our depth did not increase at that 
distance, — our greatest depth not being much more than 350 
fathoms, — Commander Bartlett thought it prudent to return 
towards shore, to the so-called axis of the Gulf Stream, and to 
run a line in a northeastern direction parallel to the coast in the 
trough of the Gulf Stream. To our great astonishment the 
depth still did not increase, and we carried from 250 to less than 
300 fathoms until we reached nearly the latitude of Cape Hat- 
teras, when in a short distance there was a very rapid drop from 
352 fathoms to 1,386 fathoms. A fifth line was run normal to 
this northern slope of the Gulf Stream plateau, to a depth of 
1,632 fathoms. A sixth line was run to the northward of Cape 
Hatteras, to a depth of 1,047 fathoms. A seventh line was run 
east, off Cape May, from the hundred-fathom line to 1,200 
fathoms. 
In accordance with an arrangement made with the late Sir 
Wyville Thomson, by which the collections made by American 
and English deep-sea expeditions were to be sent to the same 
specialists, the collections of the “ Blake” were worked up 
under the most favorable conditions. But as the greater part 
of the collections made during the third cruise of the “ Blake T 
cover the extension into deep water of the ground already in 
part occupied by the United States Fish Commission, the col- 
lections made north of Cape Hatteras were sent to the natural- 
ists to whom the collections of the Fish Commission had been 
intrusted. 
In the preparation of the final Reports published upon the 
« Blake ” collections, the special knowledge of those who have 
carefully followed the development of a limited group of inver- 
tebrates, their paleontological and geographical distribution, 
their migrations, and the causes which have probably led to the 
existing condition of things from a former geologieal period, 
has been indispensable. I cannot adequately express my thanks 
to the gentlemen who have so kindly undertaken the labórious 
task of preparing the Reports of the “ Blake ” collections. 
Without their assistance, the work would have been neither 
prompt nor satisfactory. 
