Chapter M

Margin, the whole circumference or outline of the shell in bivalves.

Marginated, having a prominent margin or border.

Membrane, a web of fibres.

Mouth, see Aperture.

Muscular impressions, marks made by the animal in adhering to the
shell.

Mottled, clouded or spotted.

Mucronate, ending in a sharp point.

Multilocular, many chambered.

Muricated, clothed with sharp spines.

N.

Nacred, pearly.

Nemoral, belonging to a wood.

Nited, glossy.

Nodose, knotty.

Nucleus, a kernel.

O.

Obsolete, obliterated.

Oblong, oval.

Ocellated, eye-like spots.

Ochreous, colour of yellow ochre.

Offuscated, darkened, clouded.

Olivaceous, of a greenish olive colour.

Operculum, which closes the aperture of the shell.

Orbicular, circular, round.

Orifice, an opening or perforation.

Ovate, shaped like an egg.

Ovoid, oval.

P.

Papillose, pimple, dotted.

Papyraceous, thin as paper.

Patulous, with a gap or opening.

Partitions, processes dividing the shells of the Nautilus, Serpula,
&c.

Pectinated, resembling the teeth of a comb.

Pedicle, the support of the Anatifera and its corresponding species.

Peduncle, a tube on which any thing is seated.

Pellucid, transparent, clear, bright.

Pentagonal, having five sides.

Perforated, pierced with holes.

Pervious, admitting passage.

Pillar, in univalves the internal continuation of the columella or
inner lips, extending from the _base_ to the _apex_.

Pinnated, winged.

Plaited, folded.

Plaits, folds.

Plicated, folded or plaited.

Posterior, see Margin.

Produced, lengthened out.

Protrude, to thrust forward.

Punctuated, like the punctures of a thimble.

Pyriform, pear-shaped.

Q.

Quadrangular, having four right angles.

Quadruplicated, having four plaits.

R.

Radiated, furnished with rays.

Radicated, fixed by the base to another body.

Rectangular, having right angles.

Recurvated, turned backward.

Recurved, bowed back.

Reflected, bent backward.

Refracted, abruptly bent.

Reniform, kidney-shaped.

Replicated, folded or plaited.

Reticulated, formed like a piece of net-work.

Retuse, ending in an obtuse sinus.

Reversed spire, see Heterostrophe.

Revolute, rolled backward.

Ribbed, having longitudinal ribs.

Ridge, the upper part of a slope.

Rostrum, the beak.

Rugose, wrinkled.

S.

Sanguinaceous, divided into chambers.

Scabious, rough, rugged.

Scalloped, indented at the edges.

Scutellated, shield-shaped.

Seam, line formed by the union of the valves.

Semi, the half.

Semi-cordate, half heart-shaped.

Semi-orbicular, shape of a half globe.

Semi-lunar, shape of a half moon.

Septiform, shape of a partition.

Serrated, like the teeth of a saw.

Sessile, sitting or seated.

Seta, a bristle.

Setaceous, covered with bristles.

Setiferous, bearing bristles.

Sinister valve, is the left valve.

Sinus, a groove or cavity.

Siphunculus, a cylindrical perforation as in the Nautilus, Spirula,
&c.

Spatulate, rounded and broad at the top.

Species, the division of a family or genus.

Spiny, thorny.

Spinous, like a hedgehog.

Spire, all the whorls in univalves except the one in which the
aperture is situated, which is termed the body.

Spiral, twisted like a corkscrew.

Squamose, scaly.

Striated, covered with thread-like lines.

Sub, almost.

Subarcuated, somewhat arched.

Subconic, somewhat conical.

Subulate, awl-shaped.

Sulcated, furrowed.

Summit, the tip or apex.

Suture, a hollow line of division in univalves, the spiral line of
which separates the wreaths.

T.

Teeth, pointed protuberances within the hinge in bivalves by which the
valves are united.

Tentacula, the feelers of snails, which inhabit shells.

Tessellated, chequered like a chess board.

Testacea, that order of animals covered with a testaceous shell.
Testaceous, consisting of carbonate of lime and animal matter.

Tortuosity, flexure.

Tortuous, twisted.

Transverse, crossways.

Trapeziform, shaped like a trapezium.

Trigonal, having three angles.

Truncated, cut short, ending abruptly.

Tubercle, knot or pimple.

Tuberculated, knotted, pimpled.

Tubular, in the shape of a hollow tube.

Tunicated, coated.

Turbinated, shape like a top or pear.

Turgid, swollen.

U and V.

Valves, the various pieces which compose the shell.

Varices, longitudinal ribs in univalve shells.

Variety, difference in species.

Vaulted, roofed.

Ventral, belonging to the belly.

Ventricose, inflated, swelled in the middle.

Vermiform, worm-shaped.

Vertex, the top of a most prominent part.

Verrucose, warted.

Verticulated, whorled.

Umbilicated, having a depression in the centre.

Umbo, the round part which turns over the hinge.

Undulated, waved.

Ungulata, shaped like a horse’s hoof.

Unilocular, chambered singly.

Univalve, shells of one valve only.

Volutions, the turnings of univalves.

W.

Whorl, a spiral convolution.

Z.

Zigzag, having reverse turnings and windings.

Zoned, surrounded by belts or girdles.

INDEX

A.

Acasta, 32

Acera, 95

Achatina, 102

_Alata_, 135

Amphidesma, 44

_Amphitritea_, 27

Amphitrite, 28

Ampullaria, 113

Anostoma, 103

Anatifera, 33

Anatina, 40

Ancillaria, 150

Ancylus, 94

ANNULATA, 25

Anodonta, 69

Anomia, 83

_Aplysiacea_, 96

Aplysia, 96

Arca, 62

Arenicola, 25

_Arcacea_, 62

Argonauta, 155

Aspergillum, 35

Auricula, 107

Avicula, 76

B.

Balanus, 31

Bivalve shells, 10

_Brachiopoda_, 84

Buccinum, 141

Bulimus, 105

Bulla, 95

_Bullacea_, 95

Bullæa, 95