A Conchological Manual by George Brettingham Sowerby (early reader books .txt) 📖
- Author: George Brettingham Sowerby
Book online «A Conchological Manual by George Brettingham Sowerby (early reader books .txt) 📖». Author George Brettingham Sowerby
bivalve shell when its extent on one side of the umbones is greater
than that on the other. When the sides are nearly equal, the term
_sub-equilateral_ is used.
INEQUIVALVE. (_in_; _æquus_, equal; _valva_, valve.) The two principal
valves differing from each other in diameter or convexity.
INFERIOR VALVE is that which is attached to sub-marine bodies. Only
applied to attached bivalves.
INFEROBRANCHIATA. Bl. The fourth family of the second section of
Paracephalophora Monoica, Bl. containing no testaceous mollusca.
INFLATED. Swelled, as Bulla, fig. 250, 252. This term can only be
applied to rotund shells of a light, thin texture. In other cases we
should use the word VENTRICOSE.
INFLECTED. Turned inwards. This term is applied to the outer lip of a
spiral shell when it turns towards the body whorl. This is the case in
Cypræa, fig. 446. See REFLECTED.
INFUNDIBULUM. Montf. (_A funnel._) A genus formed of those species of
CALYPTRÆA, Lam. which, having a spiral septum, so nearly resemble
Trochus that some authors have placed them in that genus. One species
named Patella Trochiformis. Recent from South America, fossil from the
tertiary beds. Fig. 237, 238, Calyptræa (Infundibulum) Pileus.
INNER LIP. That edge of the aperture of an univalve shell which is near
to the imaginary axis, as distinguished from the outer lip, or that
which is on the opposite side.
INOCERAMUS. Sow. _Fam._ Malleacea, Lam. Margaritacea, Bl.--_Descr._
Thick, inequivalve, sub-equilateral, triangular, deep, with the umbones
incurved; hinge formed of a series of transverse grooves.--_Obs._ The
larger valves of these fossil shells resemble the larger valve of
Gryphæa; but the hinge is quite distinct. The species described in
Mineral Conchology are found in the blue marl, at Folkstone, and in the
chalk. I. Lamarckii, (Catillus, Brong.) fig. 167.
INTERNAL CAST. The mould of a fossil shell, composed of matter which
entered the shell in a soft state, and has subsequently hardened, when,
the shell dropping off, the hardened substance which filled it is left
to represent its internal form.
INTERNAL LIGAMENT. A term used by some conchological writers signifying
that the ligament of a bivalve shell is placed within the closed part
of the hinge, so as not to be seen when the valves are shut. But the
substance, formerly called the internal ligament, is now distinguished
from the true ligament both in structure and use; and is now more
properly called the cartilage, so that when the ligament is said to be
internal, it must be understood that the internal cartilage is
unaccompanied by any ligament properly so called, and when a shell is
described as having two ligaments, as in the case of Amphidesma, it
means that the two substances are so far removed from each other in the
hinge that they are no longer confounded together.
INTERNAL SHELL is one which is enclosed in the soft parts of the
animal, as a bone is enclosed in the flesh of a human body. The Limax,
or common garden slug, which has a testaceous shield beneath its
mantle, is an instance of this.
Lea. A genus composed of several species of fresh-water shells
which are considered as differing from Melaniæ in having the anterior
termination of the aperture produced into a point in some degree
resembling the caudal canals of shells belonging to the family of
Canalifera, which are marine. Io fusiformis and spinosus are described
and figured in Lea's work on the genus Unio.
JODAMIA. Defr. A genus resembling Birostrites, except that in Jodamia
one valve overwraps the other, while in Birostrites the circumference
of the valves is equal.
IPHIGENIA. Gray. A sub-genus of Clausilia, C. biplicata, &c. Auct.
Gray's Turton, p. 214.
IRIDEA. Sw. A genus of "Hyrianæ," Sw. thus described:--"Oblong ovate;
bosses small, depressed, sulcated; inner cardinal tooth placed beneath
the outer. I. granosa, _Lam._ En. Méth. 248. fig. 9."
IRIDINA. Auct. A genus belonging to the Nayades, and resembling the
ANODONTÆ, Auct. but its peculiar characteristic is that the hinge
lamina is tuberculated or crenulated in its whole length. Sowerby
unites all the genera of the family into the genus UNIO. Fig. 150, I.
Elongata.
IRREGULAR SHELLS, are those which, being attached to, or imbedded in
other marine bodies, have no constant form, but are modified in shape
according to the substances to which they are fixed, as the Chamacea,
fig. 153 to 155.
IRUS. Oken. Comprehending PANDORA, PETRICOLA, SAXICAVA, &c.
ISOCARDIA. Lam. ([Greek: Isos], _isos_, similar; [Greek: Kardia],
_cardia_, heart.) _Fam._ Cardiacea, Lam. Chamacea, Bl.--_Descr._
Cordiform, regular, equivalve, ventricose, with distant, diverging,
involute, free umbones; hinge with two compressed cardinal, and one
distant, compressed lateral teeth in each valve; ligament external,
bifid, diverging in the direction of the umbones.--_Obs._ The shells
composing this genus are remarkable for the beautiful curvature of the
diverging umbones. European and Chinese Seas. Fig. 126, I. Moltkiana.
KEEL. A flattened ridge, resembling the keel of a ship. As that on the
back of Carinaria vitrea, fig. 488, and those on the whorls of some
spiral shells. A shell characterized by a keel or keels is said to be
carinated.
KELLIA. Turton, MYA Suborbicularis, Montague.
LABIS. Oken. MONODONTA, Lam.
LABIUM, or inner lip,--is used to express that side of the aperture
which is nearest to the axis and generally contiguous to the body
whorl. The lower part of this, when sufficiently distinct from that
part which overwraps the body whorl, is called the Columella.
LABRUM, or outer lip,--is the edge of the aperture at the greatest
distance from the axis.
LACINEA. Humph. CHAMA, Lam.
LACUNA. Turt. _Fam._ Turbinacea, Lam.--_Descr._ Globose, thin, covered
with a smooth epidermis; spire short, consisting of few rapidly
increasing whorls; aperture semilunar, rounded at the extremities;
columella oblique, reflected over part of the umbilicus; umbilicus
forming a lengthened area behind the columella. Northern shores. Fig
364, L. Pallidula.
LAGENULA. Montf. A genus of microscopic Foraminifera.
LAMELLATED. (_Lamella_, a thin plate.) When the layers of which a shell
is composed, instead of being compacted into a solid mass, are
separated, overlying each other in the manner of tiles, with the edges
prominent, the structure is said to be lamellated or foliaceous.
LAMELLIBRANCHIATA. Bl. The third order of the class Acephalophora, Bl.
consisting of bivalve shells, divided into the families Ostracea,
Subostracea, Margaritacea, Mytilacea, Polydontes, Submytilacea,
Chamacea, Conchacea, Pylorides, Adesmacea.
LAMELLIPEDES. Lam. (_Lamella_, a thin plate, _pes_, a foot.) The third
section of the order Conchifera Dimyaria, containing bivalves, with the
foot of the animal broad and thin; divided into the families Conchacea,
Cardiacea, Arcacea, Trigonacea, Nayades. Fig. 111. to 152.
LAMPAS. Montf. LENTICULINA, Bl. A genus of microscopic Foraminifera.
LAMPRODOMA. Sw. A genus of "Olivinæ," Sw. thus described:--"Mitriform;
spire produced, conic; resembling MITRELLA in shape, but the suture is
channelled; the aperture effuse at the base, contracted above; lower
half of the pillar with 6 to 7 plaits. Volutella, Zool. Ill. ii.
series, pl. 40. f. 1. (_fig. 86._ )" Sw. p. 321.
LAMPROSCAPHA. Sw. A sub-genus of "Anodontinæ," Sw. thus
described:--"Shell not winged, elongate, pod-shaped; teeth none; bosses
near the anterior extremity. Tropical America only? L. ? elongata.
_Sw._ Zool. Ill. i. 176. ensiforme, _Spix._ Braz. Test. siliquosa.
Braz. Test. pygmæa. Ib." Sw. p. 381.
LAMPROSTOMA. Sw. A sub-genus of Canthorbis (Trochus), described at p.
350, Lardn. Cyclop. Malac.
LAMPUS. Humph. TEREBRATULA, Lam.
LANCEOLATE. Lengthened like a lance.
LANISTES. Montf. Reversed species of AMPULLARIA, fig. 319.
LAPLYSIA. See APLYSIA.
LAPLYSIACEA. Lam. (properly Aplysiacea) A family belonging to the first
section of the order Gasteropoda, Lam. containing the genera Aplysia
and Dolabella. Fig. 254, 255.
LARVA. Humph. FISSURELLA, Lam.
LATERAL. (_Latus_, a side.) The lateral teeth are those which, taking
their rise near the umbones, proceed to some distance towards the sides
of the shell; as distinguished from the cardinal teeth, which receive
their full developement close to the umbones. Lateral muscular
impressions are those which are placed at a distance from each other,
on the opposite sides of the shell.
LATIAXIS. Sw. A genus of "Eburninæ," Sw. corresponding with the genus
Trichotropis. Sow. (Sw. Malac. p. 306.)
LATIRUS. Montf. A genus composed of species of FUSUS, Auct. which have
an umbilicus and are turriculated.
LAURIA. Gray. A sub-genus of PUPA, containing P. umbilicata, &c.
(Gray's Turton, p. 193.)
LEGUMINARIA. Schum. A genus composed of species of SOLEN, Auct. which
have an internal longitudinal bar or rib. Fig. 61. S. Radiatus, Lam.
LEILA. Gray? Described as having the hinge edge smooth like Iridina,
but having a "sharp siphonal inflexion." (Syn. B. M. p. 142.)
LEIODOMUS. Sw. A genus of "Buccininæ," Sw. consisting of Terebra
vittata and other similar species. This genus corresponds with Bullia,
Gray.
LEIOSTOMA. Sw. A genus of "Fusinæ," Sw. thus described, "Equally
fusiform," (with Fusus) "but ventricose in the middle; shell entirely
smooth, almost polished; inner lip thickened, and vitreous; base of the
pillar very straight. Fossil only. (_fig. 75._) L. bulbiformis. En.
Méth. 428. f. 1."
LEMBULUS. Leach. A genus composed of oval species of NUCULA, resembling
margaritacea, fig. 137.
LENDIX. Humph. PUPA, Lam.
LENGTH. See MEASUREMENT.
LENTICULAR. (_Lens._) Of a circular, convex form, as Pectunculus, fig.
134.
LENTICULINA. Lam. A genus of microscopic Foraminifera.--_Descr._
Lenticular, sub-discoidal, compressed, convolute, symmetrical; aperture
notched; chambers few in number; visible on the exterior, radiating
from the centre of the disk.
LEPADICEA. Bl. The first family of the class Nemantopoda, Bl. This
family consists of the same animals which constitute the Pedunculated
Cirripedes of Lamarck, and part of the genus Lepas in the system of
Linnæus. It contains the genera Gymnolepas, Pentalepas, Polylepas and
Litholepas.
LEPAS. ([Greek: Lepas], _lepas_, a rock.) The Linnæan name Lepas
contains all the Cirripedes or Multivalves, the different kinds of
which are not distinguished in the accounts given by early writers of
the habits of the animals. (Fig. 14 to 43.) It was formerly applied to
the Limpets or Patella. In fact, the ancient definition was "Concha
petræ adhærens," and would apply to any shells attached to rocks.
LEPTÆNA. Dalman. A genus belonging to the Brachiopoda; and thus
described:--"Hinge compressed, rectilinear, frequently exceeding the
width of the shell." It forms part of the genus Producta, Sow. Fig.
206, L. depressa.
LEPTOCONCHUS. Rüppell. ([Greek: Leptos], _leptus_, thin; [Greek:
Konchos], _conchos_, shell.) This shell resembles a young MAGILUS in
general appearance, although the animal is said to differ. In the young
Magilus also, the inner lip is reflected over the body whorl, which is
not the case in Leptoconchus. Red Sea. Fig. 11.
LEPTOCONUS. Sw. A sub-genus of Conus, consisting of Conus grandis,
amadis, duplicatus, Australis, &c. Sw. p. 312.
LEPTOLIMNEA. Sw. A sub-genus of Limnea, described as being nearly
cylindrical. Limnea elongata, Sow. Gen. fig. 6.
LEPTON. Turton. SOLEN Squamosus, Montague, and other species described
as "flat, nearly orbicular, equivalve, inequilateral, a little open at
the sides. Hinge of one valve with a single tooth, and a transverse
linear lateral one on each side; of the other valve, with a cavity in
the middle and a transverse deeply cloven lateral tooth each side, the
segments of which divaricate from the beak." To represent this genus we
have figured L. Squamosum in the plates, fig. 62. British.
LEPTOSPIRA. Sw. A sub-genus of Bulinus, thus described: "Spire
excessively long, sub-cylindrical; body whorl largest; outer lip
thickened; aperture oval; no teeth, striata, _Sw._ Chem. 135. f. 1226.
signata _Sw._" Sw. p. 335.
LEUCOSTOMA. Sw. A genus of "Achatina," Sw. described as resembling
Achatinella, but having a "thick pad" at the top of the "upper lip,"
and another over the base. L. variegata, Sw. Lardn. Cyclop. Malac. fig.
p. 172.
LEUCOTUS. Sw. A sub-genus of Natica, described as intermediate between
Sigaretus and Lacuna. SIGARETUS _cancellatus_, Lam. (Sw. Malac. p.
346.)
LICIUM. Humph. OVULA, Lam. (Ovulum.)
LIGAMENT. (From _Ligo_, to bind.) The true ligament is always external,
and serves the purpose of binding the two valves of a shell together
externally by the posterior dorsal margins. There is another substance,
called by Gray the _Cartilage_, which is elastic and of a condensed
fibrous structure, placed within the ligament, either
Comments (0)