Hawaiian Opisthobranchiates — OsTERGAARD 
133 
Fig. 15. Hexabranchus aureomarginatus n. sp. a, b , Dorsal and ventral aspects; c, oral tentacle; d, branchial 
plume; e and /, anterolateral and caudal aspects of rhinophore. (a, b, natural size; c, d , e, f, greatly enlarged.) 
in opposite directions and with right sides of 
the anterior ends of their bodies in contact so 
as to effect a reciprocal exchange of sperm. 
The egg structure consists of a flat bright- 
orange or scarlet ribbon attached by one edge 
to the substratum and wound around several 
times. It is referred to as Hexabranchus sp. in 
Ostergaard (1950: 109-110). 
Aeolidia edmonsoni sp. nov. 
Fig. 16, PI. 1 
Body elongate pyriform, truncate anterior- 
ly, tapering to a point posteriorly. Rhino- 
phores moderately long, linear, smooth, taper- 
ing toward extremities and uniting at bases; 
pellucid pale green with opaque white flecks. 
