APLYSIID. 365 
DoLABELLA, Lamarck. 
Etym.—Dolabella, a small hatchet. 
Distr.—12 sp. Mediterranean, Mauritius, Ceylon, Society 
Islands, Sandwich Islands. D. Teremidi (1xxxix, 74, 75). 
Shell hard, calcareous, trigonal, with a curved and callous 
apex. 
Animal like Aplysia, with gill near posterior extremity of the 
body and lateral crests closely appressed, leaving only a narrow 
opening ; ornamented with branching filaments. 
SIPHONOPYGE, Brown. 
Distr.—6 sp. West America, Chinese Sea. S. lurida, d’Orb. 
(Ixxxix, 76, 77). 
Shell truncated in front ; foot-lobes spread out for swimming; 
posterior part extended beyond the siphon. 
Norarcuus, Cuvier. 
Etym.—Notos, the back, archos, vent. 
Syn.—Busiris (griseus), Risso. 
Distr—i sp. Mediterranean, Red Sea, living in floating 
masses of sea-weed. N. ocellatus, Rang (1xxxix, 78). 
Animal ornamented with filaments, sometimes dendritic, foot 
narrow, lateral crests united, leaving only a narrow branchial 
slit; gills not covered by an opercular mantle-lobe. 
Notarchus was long supposed to be without a shell; it is 
present, however, paucispiral, only a millimetre in diameter, and 
concealed under the mantle at the posterior part of the visceral 
mass. 
AcuLEsIA, Rang. 
Distr.—Several sp. East Indies. A. rufa, Quoy (1xxxix, 79). 
Animal elongated, with a pointed posterior termination covered 
with filiform appendages; four long tentacles; gills ina branchial 
cavity. No shell. 
BuRSATELLA, Blainville. 
Distr.—B. Leachii, (1xxxix, 80). 
Subglobular, the natatory appendages united together on the 
back, leaving a dorsal cavity containing the anus and a large 
free gill; four ramified tentacles, and two buccal appendages. 
No shell. Is possibly identical with Aclesia, the globular shape 
being due, perhaps, to immersion in alcohol. 
<_< Sry LocuHetwvs, Gould, 1841. 
. Distr.—3 sp. New Guinea, on Fuci. S. longicauda, Quoy 
+ (Ixxxix, 81). 
Animal limaciform; cirrigerous, dilated at the sides, atten- 
. uated behind; neck distinct; tentacles four, long, linear, papillose, 
far apart; lips dilated laterally into tentacular processes. 
