128 
spirally, like a piece of paper rolled 
between the finger and thumb. 
Cordate, heart-shaped. 
Cordiform, resembling the form of a 
heart. 
Coriaceous, of a leather-like consist- 
ence, 
Corneous, of a horny colour or con- 
sistence, resembling horn. 
Coronal, relating to the crown or top. 
Coronated, crowned, or girt. towards 
the apex. See Coronated spire, p!. 
12, fig. 10. 
Corpus, the body of the shell, the last 
or greater wreath or volution in 
which the aperture is situate. 
Cortex, the anterior skin or epidermis. 
Costated, ribbed. 
Crassated, thickened. 
Crenated, notched. 
Crenulated, notched at the margin, 
scalloped. 
Crispated, rough with waving lines. 
Cuneiform, shaped like a wedge. 
Cylindrical, round like a cylinder ora 
roller. 
Cymbiform, boat-shaped. 
D 
Decollated, when the tip of the spire 
is broken off, as in some species of 
Bulinus. 
Decorticated, worn, divested of epi- 
dermis or skin. 
Decussated, generally applied ta strize 
or lines, which are crossed, or which 
intersect each other perpendicularly 
and horizontally. 
Deflexed, bent aside. 
Deltoidal, triangular, in the form of 
the Greek letter A, delta. 
Dentated, having teeth. 
Dentile, a small tooth, such as the 
tooth of a saw. 
Denticulated, set with small teeth, as 
in the genus Arca. 
Depressed, pressed down horizontally, 
low, shallow, flat. 
Dexter valve, is the right valve. 
Dextral shells, are those which have 
the aperture on the left side of the 
shell when the spire is held upper- 
most. 
Diaphanous, transparent, clear, pel- 
lucid. 
Diaphragm, the septa, which divides 
the chambers of multilocular shells 
of the genera Nautilus, &c. 
Diffuse, a term applied to the lips of 
univalves, when spread out or digi- 
tated. 
Digitated, fingered or clawed, as in 
the lobes of the outer lip of the 
Strombi, &c. ‘ 
Discoidal, is when the volutions are 
GLOSSARY. 
horizontally convolute, and forminga 
flattened spire, as in Ammonites, &c. 
Disk, the middle part of the valves, or 
prominent portion which lies between 
the umbo and the margin. 
Distant, the teeth in bivalves are said 
to be distant when remote from the 
umbones. 
Divaricated, straddling, spreading out 
widely. 
Divergent, tending to various parts or 
directions from one point. 
Duplicated, divided into plaits or folds. 
Duplicature, a fold, any thing doubled. 
E 
Echinated, bristled like a hog, set with 
spines. 
Effuse, spread out. 
Elliptical, having the form of an ellip- 
sis, Oval. 
Elongated, lengthened, drawn out. 
i" ith the margin oF 
Emarginate we 
Emarginated, $ edge» oa ads ential 
Ensiform, sabre-shaped. 
Entire, whole, uninterrupted, not di- 
vided. 
Epidermis, the outer coating or scarf 
skin of the shell, called by some 
authors the Periostracum. 
Epiphragm, a calcareous or membra- 
naceous process, which forms a door 
to the aperture of some Helices, 
when they retire to hybernate. 
Equidistant, being at the same dis- 
tance, one part from another. 
Equilateral, having both sides alike. 
Equivalve, having both valves of equal 
dimensions. 
Exoleted, worn or faded. 
Exserted, standing out, protruding. 
Extraneous, not belonging to a par- 
ticular thing. 
FE 
Falcated, bent or hooked like a scythe. 
Fasciated, filleted, or banded. 
Fasciculated, consisting of little bundles. 
Ferruginous, of an iron colour, or rust 
coloured. 
Filament, a slender thread-like pro- 
cess. 
Filiform, thread-shaped, slender, and 
of equal thickness. 
Fimbriated, fringed. 
Fissure, a cleft, slit, or narrow chasm. 
Flexuous, with angles and bendings. 
Flexure, a bending. 
Fluviatile, belonging to fresh water. 
Foliaceous, consisting of laminz or 
leaves, 
Foliated, bent into laminz or leaves. 
Fornicated, arched or vaulted, as In 
