GASTEROPODA: 323 
base of the gill; head with two grooved tentacles, eyes at their 
outer bases; mouth armed with horny jaws and covered by a 
broad veil with tentacular lobes. 
Distribution, 22 species. South America, Norway, Britain, 
Mediterranean, Red Sea, Ceylon. 
Sub-genus? Pleurobranchea, Meckel; P. Meckellu, Leve, 
Mediterranean. Synonym, Pleurobranchidium (maculatum), 
Quoy, South Australia. Mantle-margin yery narrow, not 
concealing the gill; dorsal tentacles ear-like, oral veil tentacu- 
liform. 
POSTEROBRANCH@HA, D’Orbigny. 
Type, P. maculata, D’Orbigny. Coast of Chili. 
Animal shell-less; oval, depressed, covered by a mantle 
_broader than the foot; foot oblong, bilobed behind; branchial 
plume on the left side, projecting posteriorly; reproductive 
orifice in front of gill, excretory behind; proboscis covered by 
a broad bilobed yeil; no dorsal tentacles. 
Runcrna, (Forbes) Hancock. 
Type, R. Hancocki, Forbes. 
Synonym, ? Pelta, Quatr. (not Beck). 
Animal minute, slug-like, with a distinct mantle; eyes 
sessile on the front part of the mantle; no tentacles; gills 8, 
slightly plumose, placed with the vent on the right side, at the 
hinder part of the back, beneath the mantle; gizzard armed; 
reproductive organs on the right side. 
Distribution on Conferve near high-water mark, Torbay. 
NepA, H. and A. Adams. 
Animal shell-less; mouth terminating a proboscis, which is 
long and thin; oral yeil half-moon shaped, with two lateral 
recurved tentacles. 
Distribution, 1 species. South Europe. 
SUSARIA, Griibe. 
Shell small; mantle tuberculated, extending well over both 
head and foot; notched in front. 
Distribution, 1 species. South Europe. 
UMBRELLA, Chemnitz. Chinese-umbrella shell. 
Type, U. umbellata, Pl. XIV., Fig. 18. 
Synonym, Acardo, Lam. Gastroplax, Bl. 
Shell, limpet-like, orbicular, depressed, marked by concéntri¢ 
