INTRODUCTION. XXi 
The Report on the Hydroids was written by Prof. George J. 
Allman ; on the Crinoids, by Dr. P. H. Carpenter; on the Hy- 
droids of the first expedition, by Prof. S. F. Clarke; on the 
Crustacea, by Prof. Alphonse Milne-Edwards ; on the Annelids, 
by Prof. Ehlers ; on the Myzostomid:e, by Prof. L. von Graff ; on 
the Isopods, by Mr. Harger; on the Ophiurans, by Mr. Lyman; 
on the Starfishes, by Prof. Perrier ; on the Corals, by Pourtalés ; 
on the Sponges, by Prof. Oscar Schmidt; on the Bryozoa, by 
Prof, Smitt; on the Holothurians, by.Dr. H. Théel; on the An- 
thozoa, by Prof. Verrill; and on the Pygnogonid:, by Prof. E. 
B. Wilson. Mr. Garman, who accompanied me as assistant dur- 
ing the first cruises of. the * Blake," was indefatigable in caring 
for the collections brought together, and he also wrote the 
Report on the Selachians. 
In addition to the preparation of the special Reports in their 
departments, I am also indebted to Prof. Goode and Dr. Bean, 
for additional notes on the Fishes ; to Mr. Dall, for the greater 
part of the account of the Mollusks; to Mr. Lyman, for that of 
the Ophiurans; to Mr. Fewkes, for that of the Acalephs; and 
to Prof. S. I. Smith, for that of the Crustacea. To Mr. John 
Murray I owe special thanks for his suggestions and assistance 
in writing the chapter on Submarine Deposits. Commander 
Sigsbee was kind enough to look over the chapter relating to 
the equipment of the “Blake.” Commander Bartlett of the 
Hydrographic Office has read the chapters on the Gulf Stream 
and on the hydrography of the Caribbean region; he has also 
supervised for this volume the drawing of several of the accom- 
panying maps. 
I have myself prepared the Reports on the Coral Reefs, the 
Surfaee Fauna of the Gulf Stream, the Sea-Urchins, and a few 
minor papers relating to the cruises of the “ Blake." 
To the U. S. Coast Survey Office I am of course under the 
greatest obligation for copies of the many reports, maps, and 
sections contained in that office to illustrate the hydrography of 
the West Indian region and of the Gulf of Mexico, and that 
of the Atlantic coast of the United States. Prof. James D. 
Dana has kindly read some of the chapters relating to the geo- 
logical problems discussed, and to Mr. Winsor I am indebted 
