154 LEUCONIA. 
XL  Leuconia Gray. 
Testa imperforata, ovato- oblonga, tenuis, sublaevigata; 
spira conica; apertura elongato-ovalis; plica parietalis unica, 
rarius 2; plica columellaris distineta, obliqua; peristoma eden- 
tulum, subsimplex. — Animalia in locis ab aqua marina saepe 
inundatis degentia, sed teste Clark pulmonibus spirantia. 
Leuconia Gray 1840 in Turt. Man. ed. nov. p. 227: sect. Conovuli. *) 
— Gray 1841. Syn. Brit. Mus p. 91 et 1847. Proc. Zool. Soc. 
p. 179. (gen.) 
— H. et .4. Adams 1854 in Proc. Zool. Soc. XXII. p. 36. 
-— Pfv. in Malak. Bl. 1854. p. 152. 
-—- H. et 4. 4dams 1855. Gen. rec. Moll. I. p. 247. Conf. 
supra p. 8. 
Auriculae sp. Fér. etc. 
Conovuli sp. Gray olim. 
Volvariae sp. Flem. 
Jaminia Leach Cat. teste Gray. 
Genus ex vitae ratione forsan Melampeis potius adscri- 
bendum, sed ab Alexia vix separandum. uare paucas nunc 
notas species hoc loco describamus. 
196 l. E. bidentata Montagu. 
T. imperforata, ventroso-fusiformis, solidula, sublaevigata, 
nitida, albida; spira conica, acuta; sutura linearis; anfr. 6 
plani, ultimus ?/, longitudinis aequans, inflatus, basi attenuatus ; 
apertura obliqua, anguste semiovalis, biplicata: plica parietali 
subtransversa, columellari minore subtorta;  perist. subin- 
crassatum, reflexiusculum. — Long. 6!/j,, diam. 3!/, mill. Ap. 
32/, mill. longa, 1!/, lata. (Coll. Nr. 108.) 
Voluta bidentata. Mont. 'Test. brit. Suppl. p. 100. t. 30. f. 2. *) 
— -— Dillm, Descr. Cat. I. p. 507. n. 21. 
** Pillar two-plaited ; throat smooth; peristome simple. Marine. (Gray 
ue) 
79*) Shell strong, thick, conie, and of a pure white, with six or seven 
moderately smooth, and somewhat glossy volutions, wrought with a few 
distant longitudinal wrinkles that undulate the separating line; the first or 
body whirl is two thirds of its length: the apex pointed: aperture narrow, 
about half the length of the shell, contracted at the upper angle; lips thick ; 
columella much thiekened, and folding back forms a sub-umbilicus, and is 
furnished with teeth-like plications. — Length a quarter of an inch. (Mont. 
]e) 
