74. REPORT OF NATIONAL MUSEUM, 1921. 
Museum staff holds good to a still greater extent in the division of 
marine invertebrates. In fact, so extensive is the number of these 
specialists, to whom the Museum is under great obligations, that a 
mere list of their names, with the particular group of invertebrates 
they have undertaken to work upon, must suffice for this report. 
Tt includes the following: Dr. Henry B. Bigelow (Medusae, Cteno- 
phora), Dr. L. A. Borradaile (Crustacea: Pontoniidae), Dr. L. R. 
Cary (Alcyonarians), Dr. R. V. Chamberlin (Annelids and Gephy- 
rea), Dr. N. A. Cobb (free-living Nematodes), Dr. Wesley R. Coe 
(Nemerteans), Dr. Leon J. Cole (Pycnogonids), Dr. Henri Coutiere 
(Crustacea: Crangonidae), Dr. R. P. Cowles (Phoronidea), Dr. 
Joseph A. Cushman (Foraminifera), Prof. G. S$. Dodds (fresh- 
water Entomostraca), Mr. A. A. Doolittle (fresh-water Entomo-_ 
straca), Prof. Max Ellis (Discodrilids), Dr. C. O. Esterly (marine 
Copepods), Dr. A. G. Huntsman (Ascidians), Mr. Fritz Johansen 
(fresh-water Entomostraca), Prof. Chauncey Juday (Crustacea: 
Daphniidae), Dr. C. Dwight Marsh, (fresh-water Copepods), Dr. 
Alfred G. Mayor (Scyphomedusae), Dr. Maynard M. Metcalf 
(Salpa, Pyrosoma, Protozoa), Dr. J. Percy Moore (Leeches), Prof. 
J. Playfair McMurrich (Actinians), Dr. Charles C. Nutting (Hy- 
droids), Dr. Raymond C. Osburn (Bryozoa), Dr. Henry A. Pilsbry 
(Barnacles), Capt. F’. A. Potts (Crustacea: Rhizocephalids), Prof. 
Frank Smith (Earthworms), Dr. W. M. Tattersall (Crustacea: 
Mysidacea), Dr. Aaron L. Treadwell (Annelids), Dr. Willard G. 
Van Name (Ascidians), Prof. L. B. Walton (Planarians), Dr. 
C. B. Wilson (parasitic Copepods). 
The division of mollusks, although less dependent on outside help, 
nevertheless gratefully acknowledges assistance received from vari- 
ous specialists. Thus Dr. Frank Baker, of the University of TIli- 
nois, and Dr. Victor Sterki, of New Philadelphia, Ohio, have kindly 
determined material. Through the kind cooperation of correspond- 
ents several puzzling points concerning Museum material have been 
cleared up by references to the original types or typical material in 
the collections under their care. These correspondents are Dr. H. A. 
Pilsbry, of the Academy of Natural Sciences in Philadelphia; Dr. 
F. B. Loomis, of Amherst College; and Mr. W. F. Clapp, of the 
Museum of Comparative Zoology. The Museum is under great obl- 
gation to the United States Navy Department for cooperation of a 
different kind, inasmuch as the investigations by Dr. Paul Bartsch, 
curator of mollusks, into the shipworm problem were greatly expe- 
dited through the efforts of the commanding officers of two of our 
navy yards. The deeper understanding of the subject gained through 
this investigation has greatly enhanced the value of our shipworm 
material. The officers referred to are Admiral C. W. Parks, Chief 
of the Bureau of Yards and Docks, United States Navy Department; 
