West Coast Nassariidae — Demond 
301 
bays, Southern California. I have taken N. 
fossatus from the flats at Anaheim Bay and 
MacGinitie (1935) reports this species from 
the flats at Elkhorn Slough, California. Dur- 
ing low tide at Bay Farm Island, San Francisco 
Bay, I have seen the mud dotted with hun- 
dreds of N. obsoletus. 
Behavior 
The Nassariidae are active molluscs. They 
burrow readily, leaving a small mound of 
dirt which discloses their location. By means 
of their large, muscular foot, they plow 
through the mud, usually in search of food, 
the bifurcated foot leaving a characteristic 
trail behind. 
Since most Nassariidae are burrowers, they 
avoid desiccation and can often escape from 
predators. Also, this burrowing habit, as well 
as the habit of living in sheltered bays, iso- 
lates these gastropods from the destructive 
action of waves and currents. 
There is disagreement regarding the actions 
of the Nassariidae when left exposed by the 
tide’s recession, or perhaps some species react 
in an opposite manner from others. Tryon 
(1882) says that, when the tide goes out, 
N. reticulatus buries itself in the sand to await 
the water’s return. MacGinitie (1935) also 
states that the Nassariidae burrow when ex- 
posed. However, according to Rogers (1939), 
when the tide recedes, N. trivittatus comes up 
from beneath the sand and crawls toward the 
water. 
Food and Feeding 
Because the Nassariidae are carnivorous, 
they are pests to oyster growers. They bore 
into oyster shells, insert their extensible pro- 
boscis, and eat out the contents. An adult 
Nassarius bores through a 3-year-old oyster 
shell in 8 hours, but the younger gastropods 
are far more destructive, selecting the delicate 
shells of the very young oysters and piercing 
15 or 20 in rapid succession. A month-old 
oyster is eaten in half an hour. 
These snails also bore through shells of 
other pelecypods and gastropods, devouring 
the soft parts. At Estero de Punta Banda, I 
have seen live specimens of the large Bubble 
Shell, Bullaria gouldiana, covered with hungry 
Nassarius tegula apparently enjoying a fresh 
meal at the expense of their ill-fated neighbor. 
Several authors suggest that the Nassariidae 
even attack their own kind. 
The Nassariidae are voracious scavengers. 
They have often been reported climbing into 
lobster pots for the dead bait. I have seen 
hordes of N. tegula feeding on putrid animal 
matter in the shallow pools at Estero de 
Punta Banda. 
MacGinitie (1935) describes the eating 
method of N. fossatus. When a snail discovers 
a piece of food, it turns over and lies shell 
downward with its foot held high and tightly 
wrapped about the food, which is thus hid- 
den while the animal devours it. He also 
( 1949 ) describes the powerful sucking action 
of its mouth, located at the end of the long 
proboscis which can be extended 1.5 inches. 
These snails cling so tightly to a bit of food 
that they allow themselves to be lifted en- 
tirely out of the water before relaxing their 
hold. 
That the keen olfactory sense of these gas- 
tropods is their principal means of finding 
food is thoroughly established by interesting 
experiments recorded by Cooke (1895) and 
MacGinitie (1935). 
Predators 
The Nassariidae are, in turn, eaten by larger 
animals. Keep (1935) tells of removing Nas- 
sarius from the stomach of a fish. According 
to Tryon (1883), in Italy Nassarius mutabilis 
is prepared for human consumption. Several 
authors report Nassarius shells inhabited by 
hermit crabs. At Estero de Punta Banda, I 
have seen many N. tegtda possessed by hermit 
crabs. At Bay Farm Island, numbers of N. 
obsoletus had been invaded by these crabs. Of 
the Nassariidae in the California Academy of 
Sciences collection, there are shells of N. 
catallus, N. cerritensis, and N. insculptus retain- 
