BACULITES. 1] 
The Auricule formed part of the genus Voluta of Linnzeus. 
Fig. 297. A. Jude, fig. 298. A. Coniformis. 
AURI'CULATED. Some bivalve shells, such as Pecten, fig. 
171, 172, have a flat, broad, somewhat triangular, process 
on one or both sides of the umbones, called an auricle or little 
ear. If on one side only, they are said to be wni-auriculated ; if 
- on both, they are said to be bi-awriculated. 
AURICULA’CEA. BI. The second family of the order Pul- 
mobranchiata, thus described: “Shell thick, solid; aperture 
more or less oval, always large, rounded anteriorly, and con- 
tracted by teeth or folds on the columella. This family con- 
tains the genera Pedipes, Auricula, Pyramidella. 
AURIFERA. BIL Orion, Auct. 
AU’RIFORM. (From Auris, an ear; forma, shape.) Ez. Halio- 
tes, fig. 338. 
AURISCAL’PIUM. Megerle. Anarttina, Lam. 
AVYCULA. Lam. (From avis, a bird.) Fam. Malleacea, Lam. 
Margaritacea, Bl. Descr. Inequivalve, inequilateral, folia- 
ceous, subquadrate, oblique, pearly; hinge rectilinear, drawn out 
into auricular appendages, with a small indistinct tooth in each 
valve, an elongated, marginal ligamentiferous area, widened 
near the centre. One circular, subcentral, muscular impression 
in each valve, with a series of smaller ones in a line towards the 
umbones. Obs. The Meleagrinee of Lam. Margaritiferee, Schum. 
which are included in this description, consist of the more 
rounded species, which do not present that elegant oblique form, 
from which the genus Avicula receives itsname. A. Hirundo, 
fig. 163. A. Margaritifera, fig. 164. From the latter are obtained 
oriental pearls. Fossil species occur in the London clay, &c. 
AXINUS. Sow. Descr. Equivalve, transverse; posterior side 
very short, rounded, with a long ligament, placed in a furrow, 
extending along the whole edge; anterior side produced, angu- 
lated, truncated, with a flattish lunette near the beaks. Mr. 
Sowerby, who describes this shell in the Mineral Conchology, 
does not consider his genus as established, not having seen the 
hinge. ‘ 
AX‘S. The imaginary line, around which the whorls of a spiral 
shell revolve; the extremities of the axis are pointed out in fig. 
379. a.a. See “ CoLuMELLA.”’ 
AZE'CA. Leach. Fam. Colimacea, Lam. A small pupiform 
shell, thus described by Fleming : “ Aperture of the shell oblique, 
narrow retrally.”” A. Tridens. (Turbo Tridens, Mont. Test. 
Brit. 338. t. xi. fig. 2.) Fig. 290. 
AZE’MUS. Ranz. Leach. 
BA‘CULITES. Lam. Fam. Orthocerata, Bl. Ammonacea, Lam. 
Deser. Straight conical, tubular, laterally compressed, chambers 
divided by very sinuous, lobed septa, the last elongated ; aper- 
