"Bucciniform; but the base narrow, and ending in a straight and
contracted, but rather short, channel; spire longer, or as long as the
aperture; exterior folliculated, or tuberculated; inner lip flattened,
as in _Purpura_; basal notch small, oblique; no internal channel;
crispata. En. Méth. 419, f. 2. Chem. 187, f. 1802. Capilla, Pennant,
pl. 72, f. 89, imbricata. Mart. 122. f. 1124. ? rugosa. Chem. f.
1473-4." Sw. p. 305.
POLYXENES. Montf. A genus of microscopic Foraminifera.
POMATIA. Gesner. (Gray, Syn. B. M. p. 133.) A genus of the family of
"Cyclostomidæ," described as having "an elongated shell with reflexed
lips, and a horny spiral operculum." Also a sub-genus of Snails,
containing HELIX pomatia, Auct. (Gray's Turton, p. 135.)
PORNUS. Humph. AMPULLARIA, Lam.
PORCELLANA. Adanson. MARGINELLA, Auct.
PORODRAGUS. Montf. A genus composed of species of Belemnites, placed by
De Blainville in the section characterized as swelled near the apex,
and straightened towards the base.
POSIDONIA. Brong. A genus formed on the cast of a bivalve shell, common
on schists from Dillemberg.
POSTERIOR. (_After_, _behind_.) The posterior or hinder part of a
bivalve shell, is that in which the siphonal tube of the animal is
placed. It is known in the shell, by the direction of the curve in the
umbones, which is from the posterior towards the anterior; also by the
ligament, which is always placed on the posterior part of the hinge,
when it exists only on one side of the umbones; and by the sinus (when
there is one) in the palleal impression, which is always near the
posterior muscular impression. In some shells, however, it is very
difficult for a learner to trace these marks; such bivalves, for
instance, as have the ligament spread out on both sides of the umbones;
such as are nearly symmetrical, and have the umbones consequently
straight, and a single muscular impression near the centre of the
valve. The Brachiopodous bivalves have a different position, with
relation to the animal, from the other bivalves, so that the hinge line
is the posterior extremity, and the part where the valves open, is the
anterior. The posterior extremity of the aperture of a spiral univalve
shell, is that nearest to the spire. In patelliform shells the anterior
and posterior extremities are distinguished by the muscular impression,
which is annular, enclosing a central disc in the inner surface of the
shell, excepting where it is interrupted by the place where the head of
the animal lies, which of course is anterior. The posterior is marked
_p._ in fig. 119, and 387. See ANTERIOR.
POSTERO-BASAL MARGIN of a bivalve shell is the posterior side of the
margin opposite the hinge.
POSTERO-DORSAL MARGIN is the posterior side of the hinge.
POTAMIS or POTAMIDES. Brong. A genus of fresh-water shells resembling
Cerithium in the characters of the aperture, but which may be known
from that genus by the thick, horny epidermis with which they are
coated. P. muricata, fig. 377. (Cerithium, Sow.) We think that these
shells should be placed near MELANIA.
POTAMOMYA. A genus of shells resembling Corbula, in every respect
except that of being inhabitants of fresh-water. Fig. 498, 499,
represents one of these fresh-water Corbulæ.
POTAMOPHILA. Sow. ([Greek: Potamis], _potamis_, river; [Greek:
philios], _philios_, choice.) "Conques fluviatiles," Lam.--_Descr._
Thick, equivalve, inequilateral, trigonal, covered with a greenish
brown, smooth, horny epidermis; hinge thickened, broad, with one
central, notched cardinal tooth in one valve, and two in the other,
with indistinct lateral teeth; ligament large, supported on prominent
fulcra; muscular impressions two in each valve, sub-orbicular.--_Obs._
The name given to this shell refers to its place of abode, being found
in rivers. It is the Venus sub-viridis of some authors, although being
a fresh-water shell, and having an incrassated hinge, and a smooth,
thick epidermis, it is most distinct from that genus. It is described
by Bowdich under the name Megadesma, on account of its large ligament,
and by Lamarck under that of Galathæa, a name previously used by him
for a genus of Crustacea. P. radiata, fig. 115. Megadesma appears to be
the preferable name, since it has the right of priority over
Potamophila. It is found in Africa.
PRIAMUS. A genus composed of ACHATINA Priamus, Lam. BUCCINUM
Stercus--Pulicum, Chemn. Conch. 9. t. 120. f. 1026-7. This shell is
ascertained to belong to a marine mollusc, having a horny operculum,
and therefore is justly considered to form a distinct genus, allied to
the Buccina and Struthiolariæ. Fig. 545.
PRISODON. Schum. HYRIA, &c. Auct. Fig. 144.
PRODUCED. (_Productus_, prominent.) A term applied to the spire of
univalve shells, or to any other prominent portion.
PRODUCTA. Sow. (_Productus_, produced.) _Fam._ Brachiopoda,
Lam.--_Descr._ Equilateral, inequivalve, thick, striated; one valve
generally convex, with the margin inflected, produced; the other valve
flat, or slightly convex, with the margin reflected; hinge rectilinear,
transverse.--_Obs._ The peculiarity of this genus, from which it
derives its name, is the manner in which the anterior margins of the
valves are drawn out and overwrap each other. The genus is only known
in a fossil state. Species occur in Mountain Limestone, and Transition
Limestone of older date. P. depressa, fig. 206.
PROSERPINA. Gray? Fig. 274, represents a small shell belonging to the
Helix tribe, to which it is believed, Mr. Gray has applied the name
Proserpina nitida. We do not know how the genus is defined.
PROTO. Defr. A fossil shell resembling TURRITELLA, but having a spiral
band reaching to the centre of each valve. P. terebralis, Bl.
PSAMMOBIA. Lam. _Fam._ Nymphacea, Lam.--_Descr._ Transverse, oblong,
slightly gaping at both ends; hinge with two cardinal teeth in one
valve, one in the other; ligament supported upon a prominent fulcrum;
muscular impressions two in each valve, sub-orbicular, distant; palleal
impression with a large sinus; epidermis thin.--_Obs._ The genus thus
described includes PSAMMOTÆA of Lamarck, which, according to him, only
differs in the number of teeth, and which he says are but "Psammobies
dégenerées." The difference appears to be accidental. This genus
differs from Tellina in not having a posterior fold in the margin. Fig.
100. The species are found in temperate and tropical climates.
PSAMMOCOLA. Bl. ([Greek: psammos], _psammos_, sand; _cola_, an
inhabitant.) A name given by De Blainville to shells of the genus
PSAMMOBIA, including PSAMMOTÆA of Lamarck.
PSAMMOTÆA. See Lam. PSAMMOBIA.
PSEUDOLIVA. Sw. A genus of "Eburninæ," Sw. thus described: "Shell
thick, oval, oliviform, ventricose; spire very short, acute; base with
two parallel grooves, one of which forms a notch at the base of the
outer lip; suture slightly channelled; inner lip very thick, and
turning inwards; aperture with an internal canal. Connects the
TURBINELLIDÆ with the VOLUTIDÆ. P. plumbea, Chem. 188. f. 1806, 1807."
Sw. p. 306.
PSILOSTOMATA. Bl. The third family of Aporobranchiata, Bl. containing
no genera of shells.
PTEROCERAS. Auct. ([Greek: Pteron], _pteron_, a wing; [Greek: keras],
_ceras_, horn.) _Fam._ Ailées, Lam.--_Descr._ Turrited, oval,
ventricose, thick, tuberculated; spire short; aperture oval,
terminating in a lengthened canal at both extremities; outer lip
thickened, expanded, produced into horn-shaped, hollow, thickened
spires, with an anterior sinus apart from the canal.--_Obs._ This
genus, containing the shells commonly called Devil's Claws, Gouty
Scorpions, Spiders, &c. is distinguished from Strombus by the
digitations of the outer lip. No fossil species are known. Fig. 405, P.
aurantiaca.
PTEROCYCLOS. Benson. Syn. B. M. p. 133. A genus formed of species of
Cyclostoma, Auct. which have "a groove or hole at the hinder part of
the mouth."
PTEROPODA. Lam. ([Greek: Pteron], _pteron_, a wing; [Greek: pous],
_pous_, a foot.) The first order of the class Mollusca, Lam. consisting
of molluscs whose organs of locomotion consist of a pair of wing-shaped
fins. This order contains the genera Hyalæa, Clio, Cleodora,
Spiratella, Cymbulia, and Pneumoderma. To which may be added other
genera enumerated in explanation of figures 220 to 226. They may be
thus distinguished.
1. ATLANTA. Shaped like Nautilus, symmetrical. Fig. 220.
2. SPIRATELLA. Spiral, not symmetrical. Fig. 224.
3. CRESEIS. Straight, thorn-shaped. Fig. 222.
4. VAGINULA. Straight, widened in the centre; apex pointed. Fig.
225.
5. CUVIERIA. The same; apex blunt. Fig. 223.
6. CLEODORA. Aperture with three spines; apex recurved. Fig. 221.
7. HYALÆA. Vaulted, open extremity, three-cornered; apex
tridentate. Fig. 226.
PTEROPODA. Bl. The second family of Nucleobranchiata, Bl. the shells of
which are described as symmetrical, extremely thin, transparent,
longitudinally enrolled, either forwards or backwards. The animals are
remarkable for a pair of broad, flat, natatory organs or membranaceous
fins, from which the family derives its name. It contains, in the
system of De Blainville, the genera Atlanta, Spiratella, and Argonauta,
to which may probably be added PHARETRIUM, König; ENTALIS, Defrance.
PULLASTRA. Sow. _Fam._ Conques Marines, Lam.--_Descr._ Equivalve, ovate
or oblong, transverse, inequilateral; hinge with three diverging
cardinal teeth in each valve, notched at the terminations; muscular
impressions two in each valve; palleal impression having a large sinus;
ligament external, partly hidden by the dorsal margin.--_Obs._ This
genus includes the Venerirupes of Lamarck, and several species of his
Veneres, they are found in the sand on the shores of temperate and
tropical climates. Fig. 120, P. textile.
PULMONOBRANCHIATA. Bl. The first order of the first section of
Paracephalophora monoica, containing the families Limnacea,
Auriculacea, and Limacinea.
PULVINITES. Defr. (_Pulvinus_, a cushion.) _Fam._ Malleacea,
Lam.--_Descr._ Sub-equivalve, inequilateral, compressed, thin, slightly
gaping posteriorly; one valve flat, the other rather concave; hinge
linear, short, divided into perpendicular grooves; muscular impressions
two, one sub-central, the other above it, nearer the hinge.--_Obs._
This fossil shell is imperfectly known, and it is difficult to give a
sufficient reason for separating it from Perna. It comes from the
Baculite limestone of Normandy. Fig. 170, P. Adansonii.
PUNCTATED. (_Punctatus_, spotted or dotted.) For example, see Conus
Nussatella. Fig. 460.
PUNCTICULIS. Sw. A sub-genus of "Coronaxis," Sw. (Conus) described in
Swainson's Malacology, page 311.
PUNCTURELLA. Lowe. CEMORIA, Leach.
PUPA. Auct. _Fam._ Colimacea, Lam.; Limacinea, Bl.--_Descr._
Cylindrical, generally ribbed; spire long, obtuse, composed of numerous
slowly increasing whorls; aperture sub-quadrate, rounded anteriorly,
entire; outer lip thickened; columella plaited.--_Obs._ This genus is
composed of land shells very variable in form, differing from Bulinus
in the numerous slowly increasing whorls of the spire, and in the plicæ
on the columella, and from Clausilia in the want of a clausium.
Britain, Southern Europe, East and West Indies, Mexico, &c. P. Uva.
Fig. 291.
PUPELLA. Sw. A sub-genus of Clausilia. Lardn. Cyclop. Malac. p. 334.
PUPILLA. Leach. A sub-genus of Pupa, P. marginata, Auct. (Gray's
Turton, p. 196.)
PUPINA. Vignard. MOULINSIA, Grateloup. _Fam._ Colimacea, Lam.--_Descr._
Pupiform, sub-cylindrical; last whorl less than the preceding; surface
brilliantly polished; suture of the spire enamelled; aperture circular;
peritreme thickened; a notch at the base of the inner lip; operculum
horny, spiral.--_Obs._ The species upon which this genus was originally
founded, and described in the "Annal des Sciences Naturelles," tome 18,
p. 439, (December 1829,) is a small pupiform shell, having nothing to
distinguish it but the enamelled suture and the notch in the aperture;
characters quite insufficient in themselves for the purpose of generic
distinction; at the same time sufficient to lead M. De Ferussac to the
suspicion of its having an operculum. The next species, described by
Grateloup under the name of Moulinsia Nunezii, (Ann. Soc. Linn. Burd,
Nov. 1840), presents more remarkable characters, having the spire
turned backwards and the penultimate whorl disproportionately large.
Seven additional species have been lately brought to this country from
the Philippine Islands by Mr. Cuming. They will be described by the
author in the Zoological Proceedings for 1841, and an illustrated
monograph of the whole genus is published in the Thesaurus
Conchyliorum, Part I, by the Author. It may be observed that in one of
the new species, the notch in the peritreme almost disappears, leaving
a very slight sinus. Fig. 524, 526, 527, 528.
PURPURA. Auct. ("_The shell-fish from which purple is taken_," Plin.)
_Fam._ Purpurifera, Lam. Entomostomata, Bl.--_Descr._ Oval or oblong,
thick; spire for the most part short, sometimes rather longer; external
surface generally sulcated, granulated, tuberculated or muricated;
aperture long, oval, somewhat dilated, emarginated anteriorly; outer
lip crenated, acute; columella flattened; operculum horny, with the
nucleus lateral, thin towards the columella.--_Obs._ True Purpuræ to be
found in the Lamarckian genera Buccinum, Ricinula, and others. They may
be generally distinguished by the flatness of the columellar lip, and
by the short canal or emargination, which is not reflected or raised,
as in Buccinum. The species are very numerous and very variable in
form, inhabiting the seas of temperate and tropical climates. The
animals secrete a purple liquor, which has been used advantageously for
dyeing; the origin of the famous Tyrian dye. Fig. 414, P. persica.
PURPURIFERA. Lam. (_Purpura_, purple; _fero_, to carry.) A family
belonging to the second section of Lamarck's order Trachelipoda, the
shells of which are described as having a very short recurved, or
ascending canal, or else only a notch between the inner and outer lips.
The name Purpurifera has been given to the family because the animals
which it includes, and particularly the genus Purpura, contain the
colouring matter from which the ancients obtained the well known
splendid purple. This family contains the following genera.
1. CASSIS. Outer lip thick, reflected, denticulated, canal turned
suddenly over the back; spire short; including _Cassidea_ and
_Cypræcassis_. Fig. 410 to 412.
2. CASSIDARIA. Canal turned gently upwards. Fig. 407, 408.
3. ONISCIA. Inner lip granulated; canal short. Fig. 409.
4. BUCCINUM. Outer lip thickened not reflected; canal short;
including _Cyllene_ and _Phos._ Fig. 416, 421, 422, 425.
5. NASSA. The same, with a notch or tooth at the extremity of the
columella; including _Cyclops_. Fig. 423, 424.
6. DOLIUM. Swelled, grooved spirally; outer lip not reflected. Fig.
420.
7. PURPURA. Aperture large; columellar lip flat; including
Tritonidea. Fig. 414, 415.
8. MONOCEROS. The same, with a tooth on the outer lip. Fig. 417.
9. CONCHOLEPAS. Patelliform; aperture as large as the shell. Fig.
417.
10. RICINULA. Columellar and outer lips granulated, denticulated,
outer lip digitated; including _Tribulus_. Fig. 413.
11. TRICHOTROPIS. Hairs on the epidermis, along the keels. Fig.
429.
12. TEREBRA. Elongated, with a spiral groove near the suture of the
whorls. Fig. 428.
13. BULLIA. Short; aperture wide; outer lip marginated. Fig. 427.
14. EBURNA. Like Buccinum, but the outer lip not thickened. Fig.
426.
15. HARPA. With varices at regular intervals. Fig. 419.
PUSIA. Sw. A sub-genus of Tiara (Mitra.) (Sw. Malac. p. 320.)
PUSIODON. Sw. A genus of "Lucerninæ," Sw. (Helix) thus described:
"Shell flattened, smooth; the body-whorl large, and much dilated at the
aperture; spire small, flat, of three or four contracted whorls;
aperture very oblique, sinuated, or obsoletely toothed at the base of
the outer lip, which is spreading and sub-reflected; inner lip
obsolete; umbilicus open. Zonaria Chemn. 132. f. 1188. auriculata Zool.
Ill. I. pl. 6." Sw. Malac. p. 330.
PUSIOSTOMA. Sw. A genus of the family "Columbellinæ." Sw. Thus
described: "general form of Columbella, but the outer lip is only
toothed in the middle, where it is greatly thickened; inner lip convex
between the granular teeth; punctata, E. M. 374. f. 4. mendicaria, 375.
f. 10. turturina, 314. f. 2. fulgurans. Lam." Sw. Malac. p. 313.
PUSTULARIA. Sw. A genus of "Cypræinæ," Sw. thus described: "Shell
generally marked by elevated pustules; aperture narrow and linear; the
extremities more or less produced; the teeth continued beyond, and
frequently forming elevated striæ across the lips. P. Cicercula, P.
Globulus." Sw. Malac. p. 324.
PYGMÆA. Humph. COLUMBELLA, Auct.
PYLORIDEA. Bl. The ninth family of the order Lamellibranchiata, Bl. the
shells of which are described as nearly always regular, rarely
otherwise, nearly always equivalve, gaping at both extremities; hinge
incomplete, the teeth becoming gradually obsolete; two distinct
muscular impressions; palleal impression very flexuous posteriorly.
This family is divided into: Section 1. Ligament internal; Pandora,
Thracia, Anatina, Mya, Lutricola. Section 2. Ligament external;
Psammocola, Soletellina, Solen, Sanguinolaria, Solenocurtus, Solenimya,
Panopæa, Glycimeris, Saxicava, Byssomya, Rhomboides, Hiatella,
Gastrochæna, Clavagella, Aspergillum.
PYRAMIDAL. (_Pyramidalis._) Resembling a pyramid in form. _Ex._
Cerithium Telescopium, fig. 378.
PYRAMIDELLA. Lam. (_A little pyramid._) _Fam._ Plicacea, Lam.
AURICULACEA, Bl.--_Descr._ Pyramidal, smooth, polished; spire long,
pointed, composed of numerous whorls; aperture small, modified by the
last whorl, rounded anteriorly; outer lip slightly expanded; columella
tortuous, with several folds. This is a genus of small, polished,
marine shells. Pyramidella Terebellum, fig. 342.
PYRAZUS. Montf. POTAMIS, Brongniart.
PYRELLA. Sw. A genus consisting of Turbinella Spirilla, Auct. and
similar species, having a long channel, a pyriform outline, and one
strong plait at the base of the columella, the apex of the spire is
enlarged. P. Spirillus, fig. 384. (The proper term would be Spirilla.)
PYRIFORM. (_Pyrum_, a pear; _forma_, shape.) Shaped like a pear, i. e.
large and rounding at one end, and gradually tapering at the other.
_Ex._ Pyrula, fig. 390.
PYRGO. Defr. A genus of microscopic Foraminifera.
PYRGOMA. Auct. ([Greek: Purgos], _pyrgus_, a tower.) _Order_, Sessile
Cirripedes, Lam.--_Descr._ Composed of a single conical, hollow paries,
with a small aperture closed by an operculum of four valves, and
supported upon a cup-shaped base.--_Obs._ The genera into which Leach
has divided this genus are Pyrgoma, Adna, and Megatrema; his genera
Nobia and Savignium differ in having but two valves for the operculum.
Pyrgoma differs from Creusia in having the body of the shell, i. e. the
parietal cone, simple, not divided into valves. Fig. 31.
PYRGOPOLON. De Montfort's figure of this genus appears as if it had
been drawn from the nucleus of a Belemnite.
PYRULA. Auct. (_A little pear._) _Fam._ Canalifera, Lam.
Siphonostomata, Bl.--_Descr._ Thin, oblong, pyriform, ventricose
towards the spire, gradually tapering towards the anterior of the
aperture, spire short, consisting of few volutions; aperture wide,
terminating in a long, narrow, open, canal; columella smooth, elegantly
tortuous.--_Obs._ The above description includes all the true Fig
shells, which present a most graceful form; the contour partaking of
the peculiar curve, called by painters the line of beauty. P. Ficus,
fig. 390.
PYRUM. Humph. PYRULA, Lam.
QUADRATE. (_Quadratus._) Square, applied when the outline of shells is
formed by nearly straight lines meeting at right angles.
QUADRILATERAL. Four-sided.
QUINQUELOCULINA. D'Orbigny. A genus of microscopic Foraminifera.
RADIATING. (_Radians._) A term applied to the ribs, striæ, bands of
colours, &c. when they meet in a point at the umbones of a bivalve
shell, and spread out towards the ventral margin.--_Ex._ The bands of
colour in Tellina radiata, fig. 105.
RADICATED. (_Radix_, a root.) Attached, and as it were rooted by means
of a fibrous byssus.
RADIOLATA. Lam. A family belonging to the order Cephalopoda, Lam. The
shells belonging to it are described as discoidal, with the spire
central, and the chambers radiating from the centre to the
circumference. This family contains the genera Rotalina, Lenticulina,
and Placentula.
RADIOLITES. A genus belonging to the family of Rudistes, differing from
Sphærulites, in having both the valves more conical.
RADIUS. Montf. A genus composed of OVULUM Volva, Auct. and other
similar species, having a long attenuated canal at each extremity. Fig.
442.
RADIX. Montf. A genus composed of species of LIMNÆA, having a short
spire and wide aperture.--_Ex._ L. aperta, fig. 309.
RAMIFIED. (_Ramus_, a branch.) Branched out.--_Ex._ The varices of some
Murices, &c.
RAMPHIDOMA. Schum. POLLICIPES, Leach.
RAMOSE. (_Ramosus_, branched.) Spread out into branches. _Ex._ Murex
inflatus, fig. 395.
RANELLA. Auct. (_Rana_, a frog.) _Fam_. Canalifera, _Lam._
Siphonostomata, Bl.--_Descr._ Oval or oblong, depressed, thick, with
two rows of continuous varices, skirting the outline, one on each side;
spire rather short, pyramidal, acute, aperture oval, terminating in a
canal at each extremity; outer lip thickened within, crenulated, or
denticulated, forming an external varix; inner lip spread over a
portion of the body whorl.--_Obs._ The shells composing this
well-defined genus, are for the most part covered with tuberculations,
and granulations, and from the colour and squat shape of some species,
have been likened to frogs. The Ranellæ are mostly inhabitants of the
East Indian seas. The few fossil species known, occur in the tertiary
beds. The two continuous rows of varices skirting the spire,
distinguish this genus from Triton, which it nearly approaches, and
into which some species run by imperceptible gradations. Fig. 393, 394.
Many new species were brought to this country by Mr. Cuming, and are
represented in parts 84, 85, 88, 89, 92, 93, of the author's
Conchological Illustrations.
RANGIA. Desmoulins. GNATHODON, Gray.
RAPANUS. Schum.? A genus consisting of species of PYRULA, Auct. which
are thin, much inflated, with short canals. Fig. 389, P. papyracea.
RAPELLA. Sw. A genus of "Pyrulinæ," Sw. thus described: "Shell
ventricose, generally thin, almost globose; the base suddenly
contracted, and forming a short canal, the channel almost obsolete;
umbilicus large, partly concealed by the inner lip. R. papyracea. En.
Méth. 436, f. 1." Sw. p. 307. RAPANUS, Schum. Fig. 389.
RAPHANISTER. Montf. A species of madrepore, described as a shell.
RAPUM. Humph. TURBINELLA, Lam.
RAZOR SHELL. A common name by which shells of the genus Solen, are
known in the market.
RECTILINEAR. (_Rectus_, right; _linea_, a line.) In a straight line.
_Ex._ The hinge of Byssoarca Noæ, fig. 132.
RECURVED. (_Re_, back; _curvo_, to bend.) Turned backwards; the term,
when applied to symmetrical conical univalves, is used to signify that
the apex is turned towards the posterior margin, as in Emarginula, fig.
241.
REFLECTED. (_Reflected_, to fold back.) Turned, or folded backwards.
_Ex._ The edge of the outer lip in Bulinus, fig. 282, is _reflected_,
while that of Cypræa, fig. 445 to 450, is _inflected_.
REMOTE. (_Remotus_, distant.) Remote lateral teeth in a bivalve shell,
are those that are placed at a distance from the cardinal teeth. _Ex._
The lateral teeth of Aphrodita, (fig. 123.) are remote; those of Donax,
(fig. 108) are near.
RENIELLA. Sw. A sub-genus of Malleus. Lardn. Cyclop. Malac. p. 886.
Gray states it to be only a distorted specimen of Vulsella, Syn. B. M.
p. 145.
RENIFORM. (_Ren_, a kidney; _forma_, shape.) Shaped like a kidney.
_Ex._ The aperture of Ampullaria, fig. 318.
RENULINA. Lam. A genus of microscopic Foraminifera.
REOPHAX. Montf. A genus of microscopic Orthocerata, Bl.