84 
PACIFIC SCIENCE, Vol. IV, April, 1950 
monly encountered on the shore rocks washed 
by the surf during high tide. A considerable 
number of individuals may be seen in a com- 
paratively small area. 
The first successful attempt at obtaining 
the spawn of this species was made on Octo- 
ber 26, 1920, when a specimen which was 
concealing an egg mass under its outspread 
foot was found on the shore rocks at Diamond 
Head. The mollusk and egg mass were taken 
to the laboratory for study. 
The egg mass, consisting of about 100 cap- 
sules, was somewhat flattened to accommo- 
date the animal "sitting” on it and was spread 
out suitably for being covered by the foot. 
The egg mass measured about 1x2 cm. 
through its horizontal diameters. The cap- 
sules were somewhat oblong, measured 2 
mm. in length, and contained an average of 
approximately 200 ova. 
About 1 V 2 hours after they had been taken 
off the rocks, the zygotes were in early cleav- 
age stages, having four or more cells. Sub- 
sequent investigations seemed to indicate an 
abnormal condition of development in which 
O.i mm , 
Fig. 5. Cypraea caputs erpentis Linnaeus, a, Egg 
mass; h, free-swimming veliger larva, anterior as- 
pect; c—e, shell of free-swimming veliger showing 
operculum and otocysts with otoliths; f, operculum 
in surface view. 
the early embryos assumed a variety of forms, 
many dying within the capsules. Some of the 
capsules ruptured in the course of 6 days, lib- 
erating embryos long before they had reached 
the veliger stage; in other capsules the young 
died. This abnormal condition possibly was 
caused by a faulty chemical nature of the 
water. 
More satisfactory results were obtained 
from another egg mass, also taken from shore 
rocks at Diamond Head. The embryos de- 
veloped normally to the free-swimming veli- 
ger stage, but cleavage and embryonic devel- 
opment were not investigated. 
The veliger larva, showing eyespots and 
otocysts, had a large reddish-brown area be- 
tween the eyes and on the ventral surface of 
the foot. A similar color, but much fainter, 
was also present in the veliger shell, which 
had a pitted surface similar to that observed 
in each of the preceding species of the genus. 
A flat triangular operculum was present, and 
otoliths were seen, one in each otocyst (Fig. 
5 a-f). 
Cypraea mauritiana Linnaeus 
Fig. 6 
In the morning of June 29, 1925, an egg 
mass was noticed in one of the aquarium 
tanks in which two of the mollusks were kept. 
The egg mass was lying on the bottom of the 
tank beside a rock to which it had probably 
been attached. Whether or not the animal 
had been "sitting” on the eggs, as in other 
cases observed, could not be said. There were 
about 300 egg cases in the mass. This may 
have been only a portion of those laid by the 
mollusk, inasmuch as some could have been 
eaten by the fishes which were also in the 
tank. 
The egg cases were of a somewhat tri- 
angular form and attached to one another at 
one or more points but were not imbedded 
in a gelatinous substance as in other species. 
The egg case measured about 4 mm. in length 
and 3 mm. at its widest point. The capsular 
