bo 
bo 
ZONITIDA. 
HELICARION, Fer., 1821. 
Syn.—Austenia, Nevill. ? Hoplites, Theobald, 1864. 
Distr.—95 sp. India, East Indies, Philippines, Australia, 
Abyssinia. H. flammulata, Quoy (xcii, 77). Celebes. 
Shell heliciform, rounded-oval, thin, fragile, covered with a 
very light epidermis; spire short, whorls few, the last much 
swollen; aperture large, oblong-triangular; peristome simple, 
sharp. 
Animal not entirely retractible within the shell; mantle pro- 
duced in front into two lobes upon the neck, and posteriorly, on 
the right side into a lobe partly covering the shell; foot truncated 
behind, the sole divided longitudinally into three parts. 
ZONITARION, Pfeffer, 1883. Jaw without middle tooth. Z. 
semimembranaceus, von Martens. 
oTESIA,.H. and A. Adams. (Vitrinella, Gray.) Mantle-lobe 
covering the greater part of the shell. Shell imperforate, very 
thin, spire conic. 
Famity ZONITIDA. 
Animal able to withdraw completely within its shell; provided 
with a caudal mucous pore. Jaw produced in the middle. 
Lateral teeth bicuspid, marginals acuminate, unicuspidate or 
bicuspidate. 
Shell usually depressed heliciform, umbilicated, thin, more or ~ 
less transparent, with simple, sharp peristome. 
The hyaline structure of the shell and the acute margin of the 
aperture most readily distinguish these shells from the Helicide, 
with which they are usually confounded. 
ZoniItTES, Montfort, 1810. 
Syn.—Archeeozonites, Sandb. 
Distr.—KEurope and America. Fossil. Tertiary. 
Shell subdepressed, umbilicated, very thin, more or less trans- 
parent; aperture semilunar, usually without teeth; lip thin, 
sharp. 
Animal elongated, completely retractile within the shell; jaw 
with a well-marked middle rostrum, lateral teeth bicuspid, mar- 
ginals unicuspid, sharp; foot with caudal mucous pore or slit. 
The Asiatic group Ariophanta has a similar shell, but the mantle- 
lobes are reflected upon it. 
ZONITES (restricted). (Agopis, Fitzinger, 1833. Tragomma, 
Held, 1837. Helicodes, Dumas, 1847.  Verticillus, Moquin- 
Tandon, 1855.) Labial palpi small; caudal gland reduced to a 
simple gioove, shell depressed orbicular, widely umbilicated ; 
striated above, smooth below; lip sharp, with a slight callus on 
the parietal wall. Southern Europe, Asia Minor. 12 sp. Z. 
Algirus, Linn. (xciii, 92). 
