Hawaiian Opisthobranchiates — OSTERGAARD 
iobes large, reflexed over, and partly covering, 
the shell. A posterior shield extending dors- 
ally to cover posterior part of shell. Foot 
divided into a larger anterior and a smaller 
posterior portion. Anterior portion truncate 
at both ends; posterior portion truncate an- 
teriorly and bluntly rounded posteriorly. Both 
portions of foot continuous with epipodial 
lobes and posterior shield, respectively. All 
external parts of animal pale blue with faint 
purple blotches and with numerous bright 
orange spots of various sizes scattered quite 
evenly over all. Mantle visible through semi- 
transparent shell, dark green with large orange 
Fig. 1 . Atys semistriata Pease, dorsal aspect (X 8). 
113 
Fig. 2. Haminoea crocata Pease, dorsal, ventral, and 
lateral aspects (X 2). 
hieroglyphs and small round dark-red spots. 
Length of animal, when creeping and fully 
extended, is 3 centimeters. 
Tryon and Pilsbry (1893: 363-364) give 
the following description of the shell: 
Shell ovate-elongate, moderately solid, yellow, be- 
coming orange on the latter part of the last whorl, and 
opaque above and below. Surface shining, showing 
slight, irregular growth-wrinkles and excessively fine, 
close, superficial spiral crenulated striae. Vertex narrow, 
very slightly impressed, imperforate or nearly so, 
opaque white in the center; lip inserted on the right of 
the center of the vertex, thickened; outer lip well 
curved; columella moderately concave, with a reflexed 
white callus, not folded above. 
Alt. 13, diam. SVi mm. Sandwich Is. 
A description and figures of the egg struc- 
ture of this mollusk are given in Ostergaard 
(1930). 
Hydatina physis (Linnaeus) 
Fig. 3 
Bulla physis Linn., Syst. Nat., p. 727, 1758. 
Hydatina physis Linn. Tryon and Pilsbry, Man. 
Conch. 15: 387, 388, pi. 45, figs. 14-17, 
1893. 
