Hawaiian Marine Gastropods — OsTERGAARD 
101 
0.1 mm. 
Fig. 24. Dolabrifera olivacea Pease, a, Egg 
ribbon; b, portion of egg ribbon enlarged; c, sec- 
tion of egg ribbon magnified to show arrangement 
of ova in egg envelopes; d, e, free-swimming veli- 
ger, lateral (d) and ventral (e) aspects; f-h, shell 
of free-swimming veliger showing operculum and 
otoliths. 
slit, along the genital groove to the right 
side of the buccal disk. The mollusk then 
slowly moved its head from side to side, grad- 
ually backing up and carefully avoiding any 
overlapping of the ribbon. 
As the embryos developed, the egg struc- 
tures assumed a brownish or greenish color. 
Under magnification the egg ribbon was 
found to be closely packed with hyaline cap- 
sules, globular, oval, and a few oblong in 
form, each containing from one to three ova, 
usually one ( Fig. 24c ) . The ova were about 
0.08 mm. in diameter. 
The free-swimming veliger stage was 
reached in 9 days. Larva and shell bore a 
close resemblance to those of Tethys. There 
was a well-developed, broad operculum ex- 
tending well beyond the foot. No eyes were 
present but otocysts were. The larva had a 
faint yellowish or brownish tinge, while the 
shell was pale yellowish or golden. The 
length of the veliger shell was about 0.125 
mm. (Fig. 24 d-h). 
Genus Not arch us 
Notarchus striatus Quoy and Gaimard 
Fig. 25 
An egg filament of Notarchus striatus was 
deposited in the laboratory, April 2, 1922. 
This egg structure, which was light brownish- 
yellow, was about 10 cm. in length, with a 
diameter of about 0.7 mm., and thrown into 
many irregular loops. A break in its length 
occurred in one place, as if the filament con- 
sisted of two parts (Fig. 25 a). 
Fig. 25. Notarchus striatus Quoy and Gaimard. 
a, Egg filament; b, magnified section of filament 
with early cleavage stages; c, d, free-swimming 
veliger larva; e, shell of free-swimming veliger. 
