ZONITIDA. 99 
costulately strigate above, rather smooth below; whorls 7-83, 
closely revolving, the last convex at the base; aperture lunar; 
peristome simple, thin, with a callous ring within. H. stephano- 
phora, Desh. (xciv, 13). Madeira. 
ACTINARIA, Pfeiffer, 1855. Not characterized. 4 sp. India. 
H. Pirrieana, Pfr. 
PuNcTUM, Morse, 1864. Buccal plate composed of sixteen 
distinct oblong laminz ; the teeth of the radula are quadrangular 
plates with rather short denticles, similar to Carychium. Shell 
asin Hyalina. H. minutissima, Lea. United States. 
MACROCYCLIS, Beck,1837. Shell rather thin, widely umbilicated, 
depressed; the last whorl declining toward the aperture; aper- 
ture oval-rounded; peristome simple, sharp, the extremities 
approaching and the lower somewhat reflected. Z. laxata, Fer. 
(xcili, 93). Chili. 21sp. California, Mexico, West Indies, Chili. 
SELENITES, Fischer. Shell smaller, last whorl somewhat 
flattened above. Animal having the jaw of Zonites but the 
dentition of the Testacellide. North America. Z. concavus, 
Say (xciii, 94). Dr. Fischer has made this group the type of a 
family Selenitide, characterized by the peculiarities of jaw and 
dentition. 
HAPLOTREMA, Ancey, 1881. Shell much smaller, peristome 
sharp. Z. Duranti, Newcomb. 
MoRCcHIA, Albers, 1860. -Shell widely umbilicated, depressed 
orbicular, rather thin, dark-colored, slightly striate, shining ; 
whorls five ; aperture semioval; peristome simple, acute; outer 
margin flexuous, columellar margin slightly thickened. Z. con- 
color, Fer. West Indies. 
Nanina, Gray, 1834. 
Distr.—503 sp. Universal, in tropical and subtropical regions 
of Asia, Africa and Oceanica. 
Shell heliciform, perforated, dextral or sinistral, somewhat 
depressed, thin, polished, particularly inferiorly, rounded or 
carinated at the periphery ; columellar lip short, reflected, often 
covering the umbilicus; outer lip simple or scarcely reflected. 
Animal with two anterior mantle-lobes covering a part of 
the surface of the shell; foot long and narrow, posteriorly more 
or less truncated and glandular, the pore slit-like, sometimes 
surmounted by a horn-shaped protuberance. The mantle-lobes 
possess some power. of lateral movement, and the faculty of 
expansion and retraction. 
ARIOPHANTA, Desmoulins, 1833. Shell sinistral, umbilicated, 
thin, diaphanous, the last whorl sometimes angulated or carinated 
on the periphery. Animal similar to Helix, but having a very 
large tubercular caudal gland. WN. regalis, Chemn. (xciii, 81). 
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