Biology of Conus , I — Kohn 
marized in Tables 1 and 2. It was not possible 
to follow the course of larval development, but 
Ostergaard (1950) has described the develop- 
ment of C. catus in some detail. 
Conus imperialis Linnaeus 
A female C. imperialis (no. 1983, 79 X 23 
mm.) was observed ovipositing in a depression 
on the side of a large dead coral head in 0.3 m, 
of water at Diamond Head, Oahu, on 6 July 
1956- Six capsules had been deposited when the 
rock was turned over and oviposition was in- 
terrupted. The capsules are rather long and nar- 
row, measuring about 19 X 13 mm., and do not 
rise vertically from the stalk and basal plate but 
are skewed to one side (Fig. 5). Upon return 
to the laboratory, one of the capsules was pierced 
and some of its contents withdrawn with a pi- 
pette. The eggs were uncleaved and measured 
225 /x in diameter. Eggs in the same capsule had 
not undergone the first cleavage 3.7 hr. later. 
Twenty-four hr. later, however, eggs in the same 
capsule had progressed to the 4-cell stage, which 
measured 250 /x on each side and resembled the 
4-cell stage of C. quercinus (Fig. 12 c) . 
On the 3rd day after oviposition, a second 
capsule was examined and found to contain 
embryos in the blastula stage. No further de- 
velopment took place in the cultures and all of 
the embryos appeared to be dead and were fixed 
on the 16th day after oviposition. The egg 
masses and larval development, as far as it could 
be studied, agree closely in the same species 
studied in the Seychelles Islands (Kohn, MS). 
The characteristics of the egg mass from Oahu 
are summarized in Tables 1 and 2. 
Conus le op ardus (Roding) 
A cluster of 19 very large egg capsules was 
found adrift in Kaneohe Bay, Oahu, at a depth 
of 5 m. by A. H. Banner on 25 April 1956. The 
basal plates of the capsules were confluent, hold- 
ing the entire mass together. A bright green 
filamentous alga was associated with the egg 
169 
Fig. 4. Views of an egg capsule of Conus catus 
Hwass in Bruguiere. Koko Head, Oahu, 22 August 
1956. 
mass when it was collected. However, the orig- 
inal substratum from which the mass presum- 
ably became detached is not known. The largest 
capsule measured 58 X 37 mm., exclusive of 
stalk and basal plate, and the average size was 
54 X 35 mm. This is about twice as large as 
any other known Conus egg capsule. For this 
reason the egg mass is tentatively assigned to 
C. leopardus , which is by far the largest species 
in the family in Hawaii, reaching a length in 
excess of 20 cm. The capsules were collected in 
an area where C. leopardus is known to occur. 
The capsules differ in shape from those of 
other species of Conus by having one lateral 
edge concave (Fig. 6). The capsular wall is 
roughened by numerous irregular ridges. 
It was not possible to examine the contents 
of the egg capsules until 2 days after collection. 
At that time typical veliger larvae, measuring 
345 g in maximum shell dimension, were pres- 
ent. Thus although the adults and egg capsules 
of C. leopardus are very large, the veliger larvae, 
and presumably the eggs, are not significantly 
larger than those of much smaller species (Table 
2). Indeed the veligers are much smaller than 
those of C. pennaceus ( Table 3 ) , the adults of 
which species are typically one-fourth or less 
the size of C . leopardus. 
Fig. 3- Developmental stages of Conus abbreviatus Reeve, a, 3- or 4-day embryo, in modified trochophore 
stage; b, 5- or 6-day embryo, with first trace of shell present; c, 7- or 8-day embryo, showing developing velar 
lobes; d, fully-formed veliger, 10 or 11 days, lateral view; e , as d, but anterior-lateral view; f, as d, but ante- 
rior-ventral view, showing expanded velar lobes and ventral aspect of foot and operculum, ac, Apical cilia; e , 
eye; f, foot; h, heart; m, mouth; op, operculum; ot, otocyst; ps, pigment spot; sh, shell; t, tentacle; vl, velar 
lobe; vm, visceral mass. 
