108 
The first two cleavages resulted in blasto- 
meres of equal sizes as in the typical gastro- 
pod. The embryo reached the free-swimming 
larval stage in 8 days. Larva and shell were 
clear and transparent, the operculum large 
and rounded. Otocysts were present but not 
eyes. The veliger shell measured 0.14 mm. 
in length (Fig. 3 4c, d) . 
Fig. 34. Placobranchus sp. a, Egg filament; b, 
magnified section of filament showing 4-cell cleav- 
age stage; c, d, free-swimming veliger larva. 
Family ELYSIIDAE 
Genus Elysia 
Elysia sp. 
Fig. 35 
Several animals of this genus were found 
near the laboratory close to shore. An egg 
filament was deposited in the laboratory by 
one of them on July 5, 1923. This was a 
white, cylindrical, twisted filament about 25 
mm. in length, closely packed with egg 
capsules of oval and angular shapes, each con- 
taining from two to four ova. The diameter 
of the ova was about 0.08 mm. (Fig. 35^, b). 
The free-swimming veliger stage was 
reached in the short period of 5 days, when 
the colorless larvae in a pellucid and colorless 
shell emerged from the coil. The operculum 
PACIFIC SCIENCE, VoL IV, April, 1950 
extended beyond the foot; otocysts were pres- 
ent but not eyes (Fig. 35c). 
Fig. 35. Elysia sp. a , Egg filament; b, magni- 
fied section of filament showing arrangement of 
ova and hyaline capsules; c, free-swimming veliger 
larva in lateral aspect. 
Fig. 36. Crypt odoris sp. a, Egg ribbon; b, mag- 
nified section of ribbon showing arrangement of 
ova; ' c, d, free-swimming veliger larva: c, ventral, 
and d, lateral aspects; e-g, shell of free-swimming 
veliger larva with operculum and otocysts. 
