MANUAL OF THE MOLLUSCA. 
Duminyi,* Requien; lateral cirri, 3 on each side (sometimes 4 
on one side, and 3 on the other.—Clarke). fossil, in the Coral- 
line Crag; Britain; Catania. Living, Britain; Mediterranean. 
Trochocochlea, Klein. Spire moderately raised ; base, sightly 
umbilicated in the adult, perforated in the young, pillar lip with 
a strong tubercular tooth. Lateral appendages 3 to 4 on each 
side. Example, T. lineatus, Da Costa. Britain, France, Spain, 
Mogador. 
Ziziphinus, Leach. Spire pyramidal, base imperforated ; 
pillar lip notched or angulated at the lower part. Example, 
T. granulatus, Born. 7 species, Britain. 
Omphalius, Philippi. Type, Trochus viridulus, Gmel. 
Mazatlan. 
Shell with a spiral ridge surrounding the umbilicus, ending 
in one or more tubercles on the columella. 
Distribution, 4 species. Mazatlan, China. 
Pyramis, Enida, ke. 
ROTELLA (see p. 265). 
Sub-genera. Jsanda (I. coronata), Adams. Shell orbicular, 
conical, pillar edge crenated; whorls rounded; axis umbili- 
cated ; operculum orbicular, of many whorls. 
Chrysostoma, Gray. Turbo Nicobaricum, Gmel., related to 
Isanda, Pillar edge callous; operculum horny, spiral. _ 
Microthyca, Adams, differs from Zsanda in its continuous peri- 
stome and thickened outer lip. 1 species, Japan. 
Umbonella, Adams. Shell porcellanous, smail, turbinated, 
allied to Chrysostoma, but the aperture is circular, and the axis 
imperforate. 1 species, Japan. 
LEUCORHYNCHIA, Crosse, 1867. 
Etymology, leucon, white; rhynchion, a beak: 
Type, L. Caledonica, Crosse; inhabits under stones, New 
Caledonia. 
Shell depressed, sub-discoid, umbilicated, polished, of few 
whorls; aperture rounded, not nacreous. A thick callosity 
arises from the front margin of the aperture and the columella 
lip, and is continued as a free rostrated process over the um- 
bilicus. Operculum corneous, rounded, multispiral; nucleus, 
central. 
* Adecrbis supranitida and A tricarinata are varieties. 
