The Nassariidae of the West Coast of North America between Cape 
San Lucas, Lower California, and Cape Flattery, Washington 
Joan Demond^ 
The molluscs which constitute the family 
Nassariidae are worldwide in distribution and 
include several hundred species. The family 
has long been, and still is, in need of complete 
taxonomic revision. However, such a revision 
is beyond the scope of this paper, which is 
arbitrarily limited to a consideration of those 
species of Nassariidae found living on the 
west coast of North America within the area 
between Cape San Lucas, Lower California, 
and Cape Flattery, Washington. 
A summary of the known ecology of these 
molluscs was thought valuable since the 
literature on this subject is scattered and 
difficult of access. To the author’s knowledge, 
no such compilation has previously been 
attempted. 
As far as possible, detailed synonymies, 
shell descriptions, distributional records, and 
habitat remarks have been compiled for each 
of the 12 species and two subspecies found 
in this area. Revisions of the west coast faunal 
list are suggested. A key based entirely upon 
external shell characteristics of adult speci- 
mens is presented. Illustrations of all west 
coast species are included. 
In making this study, collections were ex- 
amined at the California Academy of Sciences 
in San Francisco, at Stanford University, and 
at both the Los Angeles and Berkeley cam- 
puses of the University of California. Refer- 
ence was also made to remnants of the Josiah 
Keep Collection at Mills College. In addition, 
^ Scientific Assistant, Inter-American Tropical Tuna 
Commission, Scripps Institution of Oceanography, 
La Jolla, California. Manuscript received May 15, 1951. 
specimens were collected at several west 
coast localities. 
I wish to thank Dr. Leo George Hertlein, 
California Academy of Sciences, for making 
the collection of that institution available to 
me, for his hours of assistance, and for his 
suggestions. I am particularly indebted to 
Dr. William M. Ingram, Mills College, who 
inspired and guided the entire project. 
My sincere thanks are also extended to the 
following individuals: Dr. W. A. Hilton, 
Pomona College; Dr. Willis P. Popenoe and 
Dr. Ulysses S. Grant, University of California 
at Los Angeles; Dr. Howard Hill, Curator of 
Zoology, Los Angeles County Museum; Dr. 
A. Myra Keen, Stanford University; Frank 
R. Rogers, Photographer, and Veronica Sex- 
ton, Librarian, California Academy of Sciences. 
ECOLOGY OF THE NASSARIIDAE 
Habitat 
The Nassariidae are distributed throughout 
the marine waters of the world; the only por- 
tions of the globe where they have not been 
found is in the icy seas near the poles. How- 
ever, they occur principally in tropical and 
subtropical waters. Most of the species are 
littoral, although a few live at considerable 
depths. 
These gastropods are called mud snails, 
since many aggregate on mud flats and in the 
shallow water of bays and inlets. For example, 
I have collected Nassarius tegula in great num- 
bers from the mud flats at Estero de Punta 
Banda, Lower California, and in lesser num- 
bers from the flats of Anaheim and Alamitos 
[ 300 } 
