ZONITIDA. 23 
STENOPUS, Guilding, 1828. (Guppya, Morch, 1867. Habro- 
conus, Crosse and Fischer, 1872.) Animal with a narrow loco- 
motive disk, and a border on either side, as in Vaginula; caudal 
gland with a retractile appendage. Shell perforated, conical or 
depressed, thin, diaphanous; peristome simple. 5 sp. St. 
Vincent, W. I., Mexico, Venezuela. 8S. cruentatus, Guild (xciii, 
91). St. Vincent, W. I. 
OMPHALINA, Rafinesque, 1819. (Moreletia, Gray, 1855. Edusa, 
Albers, 1860. Zonyalina, von Martens, 1865.) Shell widely 
umbilicated, striated above, smooth below. Labial palpi large, 
caudal pore well developed. 14 sp. United States, Mexico, 
Guatemala. Z. fuliginosus, Griffith (xciii, 96). U.S. Zonya- 
lina is said to be distinguished from Moreletia by the want of 
‘the outer cervical lobe of the mantle. 
MESOMPHIX, Rafinesque, 1819. Shell umbilicated or perforated, 
globosely depressed, thin, striated, reddish horn-color, lighter 
below, shining; whorls four-and-a-half to six; aperture lunar 
ovate; peristome simple, straight, acute, extremities approach- 
ing, that of the columella subreflexed. Z. ligerus, Say (xciii, 
97). Several species, mostly Wnited States. Barely distin- 
guished from Omphalina by a more elevated spire. 
ZGOPINA, Kobelt. (Retinella, Shuttl.) Proposed for Z. olive- 
torum, Gm. (xcili, 95), and allied European species, scarcely 
distinct from the North American group Omphalina. 
HYALINIA, Agassiz, 1837. (Aplostoma, Moquin-Tandon, 1855.) 
Shell depressed or conical, more or less longitudinally, but not 
spirally striate; semitransparent, smooth and shining; umbilicus 
large, rarely small or none; epiphragm none, rudimentary or 
vitreous. Flagellum none or short, thick and steadied by a 
terminal muscle; mucous vesicles represented by a glandular 
layer. 50 sp. Mostly Europe and North America. 7. cel‘arius, 
Muller. 
VITREA, Fitz., 1853. (Crystallus, Lowe, 1854.) Shell small, 
fragile, shining, hyaline, smooth, convexly depressed, perforate 
or imperforate; whorls 4—6, the last not deflected at the 
aperture; aperture lunate, the lip simple, acute. Europe. 4. 
erystallina, Mull. 
poLiTaA, Held, 1837. (Oxychilus, Fitz., 1833. Lucilla, Lowe, 
1854. Aplostoma, Moquin-Tandon, 1855. Euhyalina, Albers, 
1857. Hyalina (restricted), Albers, 1860.) Shell convexly 
depressed or subdiscoidal, umbilicate, smooth, shining, pellucid, 
corneous, the base more or less milky opaque; aperture obliquely 
lunate; lip simple, acute. Mostly European. AH. glabra, Stud. 
ZONITOIDES, Lehm., 1864. H. nitida, Mull. Europe, United 
States. 
NAUTILINUS, Mousson, 1872. Shell nautiloid, involute. JZ. 
Clymene, Shuttl. 
