A Conchological Manual by George Brettingham Sowerby (early reader books .txt) 📖
- Author: George Brettingham Sowerby
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at a more interior part of the shell; it is sometimes contained in a
pit, formed for its reception, in the centre of the hinge. This
substance, being elastic, keeps the valves open, unless drawn together
by the counteracting force of the adductor muscles. When conchologists
speak of a shell as having the ligament external, the real meaning is
that these two substances are so close together as in appearance to
constitute one body placed outside the shell so as to be seen when the
valves are closed. When two ligaments are spoken of, as in Amphidesma,
the meaning is that the cartilage occupies a separate place on the
hinge.
LIGAMENTIFEROUS. (_Ligamentum_, a ligament, _fero_, to bear.) Having or
containing the ligament, as the cardinal pit in Mya, fig. 71.
LIGULA. Leach. A genus containing the more rounded and less gaping
species of LUTRARIA, Auct. Fig. 77, Lutraria Papyracea.
LIGULATE. (_Ligula_, a slip, a shoe-latchet.) Thin, slender, like a
slip, or neck of any thing, as the anterior muscular impression of
Lucina, fig. 104.
LIGUMIA. Sw. A sub-genus of Unio, thus described:--"Very long and
pod-shaped; bosses depressed; cardinal teeth moderate. S. recta. Lam.
1. p. 74." Sw. p. 378.
LIGUUS. Montf. A genus containing species of ACHATINA, Auct. which have
rounded apertures and lengthened spires, differing from his POLYPHEMI,
which have lengthened apertures. A. virginea, Auct. fig. 286, is the
type of this genus.
LIMA. Brug. (_Lima_, a file.) _Fam._ Pectinides, Lam. Subostracea,
Bl.--_Descr._ Equivalve, inequilateral, compressed,
oblique-auriculated, oval, radiately ribbed or striated, imbricated,
covered with a light brown epidermis; hinge with a triangular disc
between the umbones, divided in the centre by a triangular ligamentary
pit without teeth; muscular impression one, sublateral,
sub-orbicular.--_Obs._ The shells thus described are marine, two or
three species being found on our coasts, and fossil species occurring
in Lias, inferior Oolite, Calcaire-grossiér, &c. They differ from
Pecten in having a wide hiatus for the passage of a byssus, by which
they are occasionally attached, and also in the triangular disc, which
separates the umbones. The animal makes use of the valves of his shell
as natatory organs, working them like fins or paddles, and by this
means proceeding at a rapid rate through the waters. L. Squamosa, fig.
174.
LIMACINA. Cuv. (_Limax_, a snail.) _Fam._ Pteropoda, Lam.--_Descr._
Papyraceous, fragile, planorbicular, sub-carinated, obliquely
convolute; spiral side rather prominent, the other side umbilicated;
aperture large, entire, not modified, peristome sharp.--_Obs._ This is
SPIRATELLA, Bl. The shell figured as Limacina in Sowerby's Genera,
under "pteropoda," is an _Atlanta_. Our representation of Spiratella
Limacinea, fig. 224. is copied from Blainville.
LIMACINEA. Lam. A family of the order Gasteropoda, Lam. including the
following
CRYPTELLA. Spire mammillated; a septum. Fig. 256.
PARMACELLA. Flat, haliotoid, spiral. Fig. 257, 258.
TESTACELLUS. Sub-spiral. Fig. 261.
LIMAX. Incomplete. Fig. 259.
PLECTROPHORUS. Conical. Fig. 260.
VITRINA. Heliciform, hyaline. Fig. 262, 263.
LIMACINEA. Bl. The third family of the order Pulmobranchiata, Bl.
Described as containing shells very variable in form, most frequently
inclining to globular or oval; the apex always obtuse; aperture
variable, but never emarginated. All the Limacinea are phytophagous and
terrestrial. This family answers to the genus Helix of Linnæus and to
the Colimacea of Lamarck, leaving out the Auriculacea. It contains the
genera Succinea, Bulinus, Achatina, Clausilia, Pupa, Partula, Helix,
Vitrina, Testacella, Limacella, Limax.
LIMAX. _Lam._ Limacinea, Lam. and Bl.--_Descr._ Internal irregular,
sub-quadrate, scutiform, crystalline; apex rounded, indistinct;
epidermis, light brown, thin, extending beyond the margin.--_Obs._ The
shell is placed under the scutellum of the common garden slug. Fig. 25,
Antiquorum.
LIMNACEA. Bl. The first family of the order Pulmobranchiata, Bl. The
shells of this family are described as thin, with the outer lip always
sharp. It contains the genera Limnea, Physa, Planorbis.
LIMNEANA. Lam. A family of the order Trachelipoda, Lam. containing the
following genera:--
LIMNÆA. Spire produced; including _Physa_. Fig. 308 to 310.
PLANORBIS. Spire orbicular; including _Planaria_. Fig. 311, 312.
LIMNEA. Lam. ([Greek: Limnas], _limnas_, lacustrine.) _Fam._ Limnacea,
Lam. and Bl.--_Descr._ Oblong, light, thin; spire variable in length,
acute; last whorl large, aperture large, longitudinal, entire; inner
lip spread over a portion of the last whorl; columella forming an
oblique fold; outer lip rounded at each extremity, thin.--_Obs._ These
light horn-coloured shells are common in standing pools, ponds and
ditches, in various parts of Europe. They resemble the Amber shell
(Succinea) in shape, but the animal of the latter is amphibious, and
the shell of a bright amber colour. L. Stagnalis, fig. 308. L.
auricularia, fig. 309. (RADIX, Montf.) The reversed species have been
separated under the name Physa, fig. 310. Other generic names have been
given to other species.
LINES OF GROWTH. The concentric striæ or lines formed by the edges of
the successive layers of shelly matter deposited by the animal by which
it increases the shell. The outer edge of the aperture is always the
last line of growth.
LINGUIFORM. (_Lingua_, tongue; _forma_, form.) Tongue-shaped.
LINGULA. Lam. (Dim. from _lingua_, tongue.) _Fam._ Brachiopoda, Lam.
Palliobranchiata, Bl.--_Descr._ Equivalve, oblong, depressed, thin,
equilateral, gaping and pointed at the umbones, gaping and truncate or
trilobate at the opposite extremities, attached by a fleshy pedicule
fixed to the umbones.--_Obs._ This is the only bivalve shell which is
pedunculated, in which respect it constitutes a singular anomaly. The
ancient writers, seeing the valves separate, placed it in their systems
under the name Patella Unguis. There are several recent species found
in the Moluccas, and some fossils in sandy indurated marl, and in
alluvium of Suffolk. L. Anatina, fig. 219, is so named from its
resemblance to a duck's bill.
LINGULINA. D'Orb. A genus of microscopic Foraminifera.
LINTHURIS. Montf. Conch. Syst. 2. 154. A genus of microscopic
Foraminifera.
LIP. See LABIUM and LABRUM.
LIPPISTES. Montf. A genus of microscopic Foraminifera.
LITHODOMUS. Cuv. ([Greek: Lithos], _lithos_, stone; [Greek: Dôma],
_doma_, house.) _Fam._ Mytilacea, Lam.--_Descr._ Transverse, elongated,
cylindrical, equivalve, with the extremities rounded, and the posterior
extremity rostrated; umbones not prominent, terminal; hinge straight,
destitute of teeth; ligament linear, most conspicuous within; muscular
impressions two.--_Obs._ The shells composing this genus differ from
Modiola, not only in the cylindrical form, but also in the circumstance
from which the generic name is derived, i. e. of their living in
stones. Thus, while the form and structure of the shell bring it near
the Mytili or Muscle shells, the habits of the animal cause it to
approach the Lithophagi, or rock-eating molluscs of Lamarck. L.
Dactylus (fig. 161,) is the Mytilus Lithophagus of ancient authors.
LITHOLEPAS. Bl. ([Greek: Lithos], _lithos_, stone, [Greek: lepas],
_lepas_, rock.) De Blainville's name for LITHOTRYA, Sow.
LITHOPHAGIDÆ. Lam. ([Greek: Lithos], _lithos_, stone; [Greek: Phagô],
_phago_, eat or gnaw.) A family of the Conchifera Dimyaria, Lam.
consisting of terebrating bivalves, gaping anteriorly, having no
accessary valves; and containing the genera Saxicava, Petricola,
Venerupis, to which are added other genera enumerated in explanation of
figures 91 to 97. Notwithstanding the numerous genera which have been
created, I think that the most convenient arrangement will be to reduce
them to two, thus--
PETRICOLA, with distinct cardinal teeth, including, Clothe,
Venerirupis and Coralliophaga. Fig. 91, 92, 97.
SAXICAVA, without teeth, including Biapholius, Hiatella,
Sphænia, Byssomya, and Thracia. Fig. 93 to 96.
LITHOTRYA. G. B. Sowerby. ([Greek: Lithos], _lithos_, stone; [Greek:
truo], _truo_, to bore through.) _Fam._ Pedunculated Cirripedes,
Lam.--_Descr._ Eight unequal valves, forming a laterally compressed
cone, the lower central valves being very minute; pedicle fleshy, scaly
at the upper extremity; fixed at the base in a patelliform shelly
support.--_Obs._ This genus derives its name from the power possessed
by the animal of making dwelling holes in stones or pieces of rock. The
remarkable shelly cups at the base of the pedicle is regarded as
analogous to the shelly base of the Balanus, so that this genus would
form an intermediate link between the Sessile and Pedunculated
Cirripedes of Lamarck. Fig. 39, L. dorsalis. West India Islands.
LITIOPA. Ranz. _Fam._ Turbinacea, Lam.--_Descr._ "Shell not very thick,
horny, with a slight epidermis, rather transparent, conical, with
whorls somewhat rounded; the last being larger than all the rest
together; with the apex pointed, longitudinally grooved; aperture oval,
larger anteriorly than posteriorly, with the lips disunited, the right
lip simple, separated from the left by a rather indistinct notch, or a
slight emargination in the contour. The left lip slightly reflected
backwards, so as to form a kind of salient margin with the anterior
extremity of the columella, which is united, rounded, arcuated and
slightly truncated at the anterior."--_Obs._ The Molluscous animals,
whose shells are thus described, are found in the Mediterranean, and
are remarkable for the power of suspending themselves from the sea-weed
on which they live, by a thread resembling a spider's web. The general
appearance of the shell presents a medium between Phasianella and
Littorina, but it is apparently destitute of an operculum.
LITTORINA. Fer. (_Littus_, the sea-shore.) _Fam._ Turbinacea,
Lam.--_Descr._ Turbinated, thick; spire acuminated, consisting of few
whorls, about one third of the axis in length; aperture entire, large,
rounded anteriorly; outer lip thickened within, acute; columella rather
flattened; operculum horny, spiral, with rapidly increasing
volutions.--_Obs._ The shells composing this genus are known from Turbo
and Phasianella by the horny operculum; and from Trochus, which has
also a horny operculum, by the small number of the whorls. The
Littorinæ, among which may be enumerated the common Periwinkle, are, as
the name implies, found on sea shores, feeding upon seaweed, in all
parts of the world. Fig. 363, _L. Vulgaris_.
LITUACEA. Bl. The second family of Polythalamacea. Bl. The shells are
described as chambered, symmetrical, convolute in part of their extent,
but constantly straight towards the termination. The genus Spirula,
which is admitted into this family, does not properly belong to it, any
more than to the Lituolæ of Lamarck, in which it is also placed. It
does not agree with the descriptions of either. This family partly
corresponds with the "Lituolées," Lam. and contains the genera Lituola,
Ichthyosarcolites, Spirula, Hamites and Ammonoceras.
LITUACEA. Lam. A family of the order Polythalamous Cephalopoda, Lam.
containing the genus Spirula, fig. 471.
LITUITUS. Montf. SPIROLINA, Lam. Microscopic.
LITUOLA. Lam. A genus of microscopic Foraminifera.
LITUOLÆ. Lam. The third family of Polythalamous Cephalopoda, Lam. the
shells of which are described as partially spiral, the last whorl
continuing in a straight line. The transverse septa which divide the
chambers, are in general pierced by a siphon which breaks itself off
before it reaches the succeeding septum. This family contains the
genera of microscopic Foraminifera Lituola and Spirolina. The genus
Spirula, also placed in this family, does not by any means agree with
Lamarck's definitions "the last whorl continuing in a straight line."
LITUUS. Humph. CYCLOSTOMA? Lam.
LIVID. (From _lividus_.) Of a pale, dull, blue colour. The adjective is
sometimes used as a specific name. _Ex._ Conus _lividus_, Sanguinolaria
_livida_.
LOBARIA. Schum. SANGUINOLARIA rosea, Lam. (fig. 98) and other similar
species.
LOBATE or LOBED. Divided into parts.
LOBATULA. Fleming. A genus composed of two very minute species of
chambered shells. Serpula lobata and S. concamerata, Mont. Test. Brit.
515.
LOMASTOMA. Rafinesque. An imperfectly defined genus, probably belonging
to the Limnacea.
LONGITUDINAL. Lengthwise. Longitudinal striæ, ribs, &c. are those which
radiate from the apex and follow the spiral direction of the whorls, in
spiral shells; and from the umbo to the ventral margin in bivalves. The
term "decourantes" is employed by French conchologists. The bands in
Achatina, fig. 286, are longitudinal or spiral.
LORIPEDES. Poli. A genus composed of species of LUCINA, Auct. in which
the lunules are not prominent.
LOTORIUM. Montf. A genus composed of species of TRITON, Auct. in which
the aperture is effuse. T. Lotorium, fig. 400.
LOTTIA. Gray. PATELLOIDA, Quoy and Gaimard.
LUCERNA. Humph. A generic name applied to some species of Helix
included in De Ferussac's sub-genus Helicogena.
LUCERNELLA. Sw. A genus of "Lucerninæ," Sw. thus described: "Teeth on
both sides of the aperture; surface regularly and distinctly striated.
Circumference convex."
LUCIDULA. Sw. A sub-genus of Lucerna, Humph. thus described: "Aperture
transverse, both lips much thickened and united; the outer with
marginal obsolete teeth at the base; umbilicus closed.
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