Hawaiian Marine Gastropods — OSTERGAARD 
77 
11 (10) Filament large, forming an el- 
liptical loop. Length 18 cm., 
diameter 4 mm. Color white. 
. . . Pleurobranchus sp., p. 107. 
Filament small, forming a cir- 
cular loop. Length 3 cm., di- 
ameter 1 mm. . Bulla sp., p. 103. 
12 (10) Filament slender and tapering 
to an acute point at the 
ex- 
tremities 
13 
Filament thick with obtuse 
or 
blunt extremities with 
or 
without spiral twists . . . 
14 
Filament forming one volution 
without loops. Length 
19 
mm., diameter 1 mm. Color 
white 
. . . Placobranchus sp., 
p. 107. 
Filament with a few irregular 
loops. Length 23 mm., diam- 
eter 0.5 mm. Color white. . 
Elysia sp., p. 108. 
14 ( 12 ) Filament with one or two turns, 
flatly arranged. Length from 
2.5 to 4 cm. Color white. . . 
Morula dumosa, p. 96, 
and Haminoea crocata, p. 104. 
Filament with three and a half 
spiral turns, with one end at- 
tached to a gelatinous base or 
to the substratum. Length 35 
mm., diameter 3 mm. Color 
white 
. Bullina scabra solida, p. 103. 
15(5) Ribbon attached by one edge or 
by a basal support to substra- 
tum 16 
Ribbon attached flatly to sub- 
stratum 22 
16 (15) Ribbon a much-folded mass at- 
tached by a basal support to 
substratum about 2.5 cm. in 
height and 1.5 cm. in width. 
Color white 
Hydatina amplustre, p. 102, and 
H. physis, p. 102. 
Ribbon attached by one edge to 
substratum .......... 17 
17 (16) Ribbon very large and intensely 
folded, forming three or four 
circularly wound volutions 
which measure about 13 cm. 
across. Color pink 
. Umbraculum sinicum, p. 105. 
Ribbon small and with only 
slight folds or none 18 
18(17) Ribbon rising vertically from 
margin of attachment .... 19 
Ribbon sloping outward from 
centrally placed margin of at- 
tachment 21 
19(18) Ribbon of one volution; ex- 
tremely small white band, 
about 4 mm. in length .... 
..... Glossodoris sp., p. 109. 
Ribbon of 2 to 3 volutions, 2 to 
3 cm. across the mass .... 20 
20 (19) Ribbon bright scarlet or deep 
orange, forming two volu- 
tions, about 14 cm. long and 
6 mm. wide 
. . . Hexabranchus sp., p. 109. 
Ribbon bright yellow, forming 
3 volutions, about 1 1 cm. 
long and 4 mm. wide .... 
..... Cryptodoris sp., p. 109. 
21 (18) Ribbon with one volution. Di- 
ameter of entire structure 
about 1 cm. Color bright 
yellow. . . Aeolidia sp., p. 110. 
Ribbon with several irregular 
volutions, 7 mm. wide. Color 
white. . . Melibe pilosa, p. 111. 
22 (15) Ribbon with numerous parallel 
loops, not overlapping, 0.33 
mm. wide. Clear and color- 
less. 
. . Dolabrifera olivacea, p. 100. 
Ribbon not looped, forming a 
half circle, about 3 cm. long, 
2 mm. wide. Colorless. . . . 
Siphonaria normalis 
amara, p. 111. 
23 ( 1 ) Egg structure consists of groups 
of unattached, minute cap- 
sules, each containing 1 or 2 
ova. The capsules about 0.2 
mm. in diameter 
Littorina pintado, p. 97. 
