302 
PACIFIC SCIENCE, Vol. VI, October, 1952 
ing crab remnants. This evidence seems to 
indicate these species are preyed upon, or at 
least have their shells appropriated, by hermit 
crabs. 
Some Nassariidae seem adapted to escape 
particular enemies. A striking behavior was 
observed by Bauer (Flattely, 1922). He 
watched Nassarius reticulatus flee a pursuing 
starfish, Astropecten hispinosus. The snail fled 
by curious leaps, using its foot as a lever, in 
the manner of a cockle. The movement was 
such a convulsive one that Bauer found it 
difficult to follow, but it appeared to be a 
kind of somersault. This escaping reflex oc- 
curred only when the gastropod was directly 
touched by the starfish. Also, the snail’s body 
was not everywhere equally sensitive to this 
stimulus; only when the two tails of the mol- 
lusc’s foot were touched was the reaction 
produced. Bauer was unable to induce the 
reflex either mechanically or chemically — only 
through the medium of a starfish. 
Oviposition 
The Nassariidae are dioecious. They lay 
eggs in strong, leathery capsules, the capsules 
of each species having a characteristic appear- 
ance. Each capsule contains a varying number 
of ova, and there is competition among the 
embryos within the capsule, so that only a 
very small percentage survive. 
According to Tryon (1883), Nassarius reti- 
culatus deposits its spawn on various objects, 
such as Zoster a leaves, which are out of the 
water only during spring tides. These egg- 
capsules are tiny, compressed pouches, sup- 
ported by a tiny stalk and arranged in closely 
overlapping rows. The larvae remain within 
the capsule for several days after hatching 
before escaping through a small aperture at 
the top of the capsule. 
Tryon (1882) says N. obsoletus lays its ova- 
capsules during April and May. These cap- 
sules are attached singly and are crowded 
together. During May, I have seen thousands 
of capsules of obsoletus at Bay Farm Island. 
The capsules were attached to pilings, to 
living and dead gastropods and pelecypods, 
to rocks, driftwood, and the inside of an old 
rubber tire. 
Ricketts and Calvin (1948) state that ovi- 
positing N. fossatus may be found among 
eelgrass during late summer. Burch (1945) 
says fossatus is not seasonal; he records their 
spawning in Anaheim Bay during January. 
The egg-laying process of N. fossatus has 
been observed and recorded in detail by 
MacGinitie (1931). 
Adaptation to Environment 
The recurved anterior canal of most Nas- 
sarius shells aids those gastropods living on 
a muddy substrate. This structure protects 
the animal’s respiratory organ, the siphon, 
which projects above the mud, thus allowing 
the snail to breathe while concealed in the 
sediment. 
In many cases, the color of Nassarius shells, 
by blending with the environment, protects 
the inhabitants from discovery. For example, 
the shell of N. obsoletus is dark brown or 
blackish, so it is not easily seen on the mud. 
The body of this mollusc, too, is a dark color, 
like the muddy sand in which the animal 
lives. N. obsoletus is made even more incon- 
spicuous by its somewhat latticed shell sur- 
face. Particles of substrate collect in the 
irregularities of this surface and conceal the 
shell. 
TAXONOMIC STUDY 
Family NASSARIIDAE 
These gastropods usually possess a more 
or less ovate shell with a raised spire and a 
short, recurved anterior canal. Typically, a 
callus covers the inner lip, often spreading 
over the body whorl. 
Characteristically, these molluscs develop 
a long siphon and a broad foot. In almost 
all species, the foot is divided posteriorly 
into two slender appendages; the only west 
coast species lacking such bifurcation is Nas- 
sarius obsoletus. Eyes are present on the outer 
bases of the tentacles. The operculum is 
