Part 14

HARPA. Brug. (_Harpa_, a harp.) _Fam._ Purpurifera, Lam. Entomostomata, Bl.--_Descr._ Oval, ventricose, longitudinally and regularly costated; spire short, with rounded, dome-like whorls; aperture wide, emarginated; outer lip thickened, reflected, composing the last costa or rib; inner lip polished, spread over part of the body whorl, terminating in a point.--_Obs._ This beautiful genus of shells is so clearly defined by the regular, longitudinal ribs that adorn the external surface, suggesting the idea of a stringed instrument, that there is no danger of confounding it with any other. H. multicostata, (Buccinum costatum, Linn.) and H. ventricosa, are among the most elegant of the testaceous productions of the sea both in form and colouring; the former is rare. The recent species are not numerous, they inhabit the Indian Ocean. A fossil species occurs at Grignon, near Paris. Fig. 419, H. ventricosa.

HARPAX. Parkinson. Part of PLICATULA, Auct.

HARPULA. Sw. A group of shells separated from VOLUTA, Auct. thus described, "shell generally tuberculated or longitudinally ribbed; apex of the spire papillary, smooth, and in general distorted; pillar with numerous distinct plaits; the upper, small and slender, the lower, thickest and shortest."--_Type_, H. Vexillum. (Voluta, Auct.)

HAUSTATOR. Montf. A genus proposed to include those species of TURRITELLA, Auct. which have angulated whorls.

HAUSTELLARIA. Sw. A sub-genus of Murex, consisting of species with long canal and no spines. Murex Haustellum, fig. 396.

HAUSTRUM. Humph. PURPURA, Lamarck.

HELCION. Montfort. A genus composed of species of Patella, which have the apex distinctly and prominently bent forwards. _Ex._ P. pellucida, fig. 230.

HELENIS. Montf. A genus of microscopic Foraminifera.

HELICELLA. Fer. One of the sub-genera into which De Ferussac has divided the genus Helix, consisting of depressed species with large umbilicus, such as Helix Algira, fig. 279. Gonites Montf.

HELICIFORM. Shaped like shells of the genus Helix.

HELICIGONA. One of De Ferussac's sub-genera of the genus HELIX, consisting of angulated species, such as Carocolla Lamarckii, fig. 277.

HELICINA. Lam. _Fam._ Colimacea, Lam. Ellipsostomata, Bl.--_Descr._ Globose, compressed, or angulated, generally light and thin; aperture trigonal or semilunar; outer lip thickened and generally more or less reflected; inner lip spread over the body whorl, frequently callous near the columella, which is short, and terminates in a notch, angle, or slight callosity.--_Obs._ This genus of land shells, distinguished from the genus Helix, by having an operculum and a thickened columellar lip, differs also from Cyclostoma in having the aperture semicircular or angular, the peritreme discontinuous and the operculum concentric. These shells are generally small in size, and simple in form. Lamarck describes only three or four species. Mr. Gray described some others in the Zoological Journal, and in a work shortly to be published by the author, a monograph of the genus will contain descriptions and figures of at least 60 distinct species; some of which have been lately brought to this country by Mr. Cuming from the Philippine Islands. They mostly belong to tropical climates.

HELICITES. Bl. Part of the genus NUMMULITES, Lam. ROTALITES and EGEON, Montf.

HELICOGENA. Fer. A sub-genus of Helix, consisting of species, which, like the common garden snail, fig. 268, are globose and simple in form.

HELICOLIMAX. Fer. VITRINA, Drap. H. Pellucida, fig. 263.

HELICOPHANTA. Fer. A sub-genus of Helix, consisting of ear-shaped species with large open apertures.

HELICOSTYLA. Fer. A sub-genus of Helix, consisting of species with numerous whorls, as H. Epistylium, fig. 281.

HELISOMA. Sw. A sub-genus of Planorbis. Sw. p. 337.

HELIX. Auct. _Fam._ Colimacea, Lam.--_Descr._ Orbicular, light, generally globular; spire short, last whorl ventricose, aperture oblique, peritreme reflected, interrupted by the most prominent part of the body whorl; columella confluent with the outer lip, and contiguous to the axis of the shell. No operculum; a thin epidermis.--_Obs._ The land shells composing this genus are found in all parts of the world; the common snail, H. Aspersa, is well known as a destructive animal in our gardens. The genera Helix, Achatina, Bulinus, Clausilia, Anostoma, &c., have been united under one generic name by De Ferussac, and again divided under the following sub-generic names, each of which we shall illustrate by a figure. GENUS HELIX: _Sub-genus_ 1, _Helicophanta_, consisting of species with large apertures, like Vitrina; Helix brevipes. _S. gen. 2_, _Cochlohydra_, Succinea Amphibia, Drap. _S. gen. 3_, _Helicogena_, consisting of the common species with the last whorl large; Helix Hæmastoma, H. Contusa, (Streptaxis, Gray,) H. Aspersa. _S. gen. 4_, _Helicodonta_, consisting of species with teeth or folds on the columella; Polydonta, Montf. Anostoma, Helix Nux-denticulata. _S. gen. 5_, _Helicigona_, Carocolla, Geotrochus. _S. gen. 6_, _Helicella_, consisting of depressed species with a large umbilicus; H. Citrina (Naninia, Gray.) _S. gen. 7_, _Helicostyla_, consisting of species with a simple aperture, like the Helicogenæ, but with the whorls increasing very gradually; H. epistylium. _S. gen. 8_, _Cochlostyla_, Bulinus. _S. gen. 9_, _Cochlitoma_, Achatina. _S. gen. 10_, _Cochlicopa_, Polyphemus Glans. _S. gen. 11_, _Cochlicella_, Bulinus decollatus. _S. gen. 12_, _Cochlogena_, Azeca tridens. _S. gen. 13_, _Cochlodonta_, Pupa Uva. _S. gen. 14_, _Cochlodina_, Clausilia macascarensis, Balea fragilis. The last three sub-genera are included in the genus Odostomia of Fleming. We give an example of each of these sub-divisions, for the sake of presenting the reader with the principal variations to which the genus is subject. The established genera will be characterized in their places. Fig. 254 to 281.

HELIXARION. Fer. VITRINA, Drap. Differing from Helicolimax in the structure of the animal. Fig. 262.

HEMICARDIUM. Cuv. ([Greek: hêmisus], _hemisus_, half, [Greek: Kardia], _cardia_, heart.) CARDIUM Hemicardium, fig. 123**, and several similar species.

HEMICYCLA. Sw. A sub-genus of Helix.

HEMICYCLONOSTA--see CARDILIA.

HEMICYCLOSTOMATA. Bl. The fourth family of Asiphonibranchiata, Bl. described as "more or less globular, thick, flattened on the under side; spire very short; aperture large, semilunar, entire; its outer edge hollowed; its inner or columellar edge straight, sharp and septiform." This family answers to the genus _Nerita_ of Linnæus, and to the family Neritacea of Lamarck. It contains the genera Natica, Nerita, Neritina, and Navicella.

HEMIMACTRA. Sw. A sub-genus of Mactra, thus described: "General form of _Mactra_; but the cardinal teeth entirely wanting; cartilage internal, central, in a large triangular cavity; lateral teeth 2/1, distinct, lateral, striated: connected to the _Glycimeri_. H. gigantea, _Lam._ v. 472. No. 1. grandis, _Sw._ Sp. Nov." Sw. p. 369.

HEMIMITRA. Sw. A sub-genus of Paludomus, Sw. (Melanianæ.)

HEMIODON. Sw. A sub-genus of Anodon, described as having "Tubercles or undulations on the hinge margin. H. undulatus, purpurascens and areolata."

HEMISINUS. Sw. A sub-genus of Melania, thus described: "General shape of _Melania_; but the base of the aperture is contracted and emarginate; outer lip crenated. H. lineolata, Griff. Cuv. xii. pl. 13. fig. 4."

HEMITOMA. Sw. A sub-genus of Emarginula, thus described: "Patelliform; the fissure not cut through the shell, but merely forming an internal groove. H. tricostata, _Sw._ Sow. Gen. fig. 6."

HEMITROCHUS. Sw. A sub-genus of Geotrochus, Sw. H. hæmastoma. Sw. p. 331.

HEPTALASMIS. Leach. ([Greek: Hêpta], _hepta_, seven; [Greek: elasma], _elasma_, plate) A small shell resembling Pentelasmis, from which it differs in the number of valves, being composed of seven valves according to Leach, and of eight according to Gray, who counts the dorsal valve, which is jointed, as _two_, and names his genus Octolasmis. Fig. 41, H. Warwickii.

HERCOLES. Montf. A microscope shell, appearing from De Montfort's figure to resemble TROCHUS _Imperialis_ in shape.

HERION. Montf. LENTICULINA, Bl. Microscopic.

HERMAPHRODITA. Bl. The third sub-class of Paracephalophora, Bl. divided into, Sect. 1, _symmetrical_, containing the orders Cirrobranchiata and Cervicobranchiata; Sect. 2, _non-symmetrical_, order, Scutibranchiata.

HERMES. Montf. A genus composed of CONUS _Nussatella_, Auct. and other elongated, cylindrical, striated species. Fig. 460.

HETEROBRANCHIATA. Bl. The fourth order of the class Acephalophora, Bl. containing no testaceous mollusca.

HETEROPODA. Lam. The fifth order of the class Mollusca, Lam. This order contains but one genus of shells, viz. Carinaria, fig. 488.

HETEROSTEGINA. D'Orb. A genus of microscopic Foraminifera.

HIATELLA. Daud. Fam. Lithophagidæ, Lam. A genus composed of species of Saxicava, Auct. which have sharp, angulated, posterior ridges, a circumstance which occurs to many species in a young state, which afterwards become rounded off. Fig. 95, Hiatella biaperta.

HIATULA. Sw. A genus proposed to include those species of Oliva, Auct. which have widened apertures. _Ex._ O. Subulata, fig. 458.

HIBOLITHES. Montf. A genus composed of species of Belemnites, Auct. which are swelled towards the apex, and contracted near the centre. B. Hastatus, Auct. fig. 468.

HIMANTOPODA. Schum. MALLEUS, Auct.

HINGE. The edge of the bivalve shells near the umbones, including the teeth and ligament.

HINNITES. Defr. A generic name proposed for PECTEN PUSIO, Auct. remarkable for the irregularity of the outer surface, which would almost lead to the belief of its being an attached shell. Fig. 173, H. Pusio.

HIPPAGUS. Lea. (_Horse boat._) A minute fossil shell, resembling Isocardia in form, but destitute of hinge teeth. H. Isocardioides, fig. 128.

HIPPOCHRENES. Montf. Species of ROSTELLARIA, Auct. with the outer lip spread. Fig. 403. R. Columbaria.

HIPPONYX. ([Greek: Hippos], _hippos_, horse; [Greek: onux], _onyx_, nail or hoof.) _Fam._ Rudistes, Lam.--_Descr._ Inequivalve, sub-equilateral, rather irregular, destitute of ligament and hinge teeth; lower valve attached, flat, sub-orbicular, with a muscular impression, composed of two lunulate portions, meeting at one extremity, and presenting the form of a horse-shoe; upper valve conical, with the apex inclined backwards, and the muscular impression marginal.--_Obs._ The earlier naturalists having only met with the upper valve of these shells, placed them among the patelliform univalves; to some of which, particularly Pileopsis, they bear a very strong resemblance. The species of Hipponyx are numerous, and till lately only known in a fossil state. The recent species belong to tropical climates: the fossil species are found in the tertiary beds. Fig. 199, H. Cornucopia.

HIPPOPODIUM. Conybeare. _Fam._ Cardiacea, Lam.--_Descr._ Equivalve, obliquely transverse, heavy, deep, inequilateral, umbones incurved; ventral margin sinuated, so as to give a bilobed appearance to the shell; hinge incrassated, with one rugged oblique tooth.--_Obs._ These fossils are found in the upper beds of Lias. Fig. 129, H. Ponderosum.

HIPPOPUS. Lam. ([Greek: Hippos], hippus; [Greek: pous], _pous_, foot.) _Fam._ Tridacnacea, Lam.--_Descr._ Equivalve, inequilateral, regular, subquadrate; lunule closed, flat, with crenulated edges; ventral margin deeply undulated; external surface fluted, with radiating ribs, which are transversely fringed with rows of tubular spines; hinge margin thick, with two long, compressed posterior lateral teeth in one valve, three in the other; ligament marginal, external.--_Obs._ The shell thus described is rightly separated from Tridacna, on account of the anterior dorsal margins being closed; whereas in Tridacna there is a wide hiatus. Only one species of this genus is known, which receives its name from its resemblance in form to a horse's foot, when held with the flat anterior dorsal margin downwards. Few shells are found to concentrate so many beauties as the Hippopus Maculatus, commonly called the Bear's-paw-clam; the delicate whiteness of the interior, the undulating edge, the radiated fluted columns, adorned at intervals by crisped fringes, and the richness of the variegated colouring, are such as to secure the admiration of the most superficial observer. From the Indian Archipelago. Fig. 156, H. Maculatus.

HIPPURITES. Montf. _Fam._ Orthocerata, Lam. Rudistes, Bl.--_Descr._ Tabular, rude, irregular, attached; lower valve cylindrical, more or less lengthened, apparently divided into sections by septa (considered by some authors as merely projecting layers of growth) having one or two lateral tubes within; upper valve round, flat, fixed on the aperture of the tubular valve like an operculum.--_Obs._ This genus is known only in a fossil state, and but very imperfectly. Lamarck places it among his chambered Cephalopoda, &c. De Blainville, considering it a true Bivalve, enumerates it among his Rudistes. Cretaceous group. Fig. 198, H. Cornucopia.

HORTOLUS. Montf. SPIROLINA, Lam. Microscopic.

HYALÆA. Auct. (_Hyalus_, glass.) _Fam._ Pteropoda, Lam. Thecosomata, Bl.--_Descr._ Globose, glassy, transparent, with a triangular opening at the upper part where the dorsal portion advances beyond the ventral; ventral portion vaulted; dorsal more flat; lower extremity tridentate.--_Obs._ The singular structures composing this genus were formerly taken for bivalves, and named Anomia Tricuspidata, &c. They are now known to belong to the class of molluscous animals, called Pteropoda, from the wing-shaped organs of locomotion. A species of Hyalæa occurs in Sicily in a fossil state. Recent species are found in the Mediterranean, Atlantic, and Indian Oceans. Fig. 226, H. Tridentata.

HYALINA, Studer. VITRINA, Drap.

HYALINE. (_Hyalus_, glass.) Glassy, thin, transparent--_Ex._ Carinaria Mediterranea, fig. 488.

HYDROBRANCHIATA. Bl. The first section of the order Gasteropoda, Lam. containing Molluscs which breathe water only; divided into the families Tritoniana, Phyllidiana, Semi-phyllidiana, Calyptracea, Bullæana, and Aplysiana.

HYGROMANES. Fer. A sub-division of Helix, containing H. limbata, Auct. &c. Gray's Turton, p. 143.

HYRIA. Lam. A genus composed of species of Nayades, distinguished by their alated dorsal margins, and lamellated lateral teeth. South America. HYRIA corrugata, fig. 143, Hyria Syrmatophora, fig. 144.

HYRIDELLA. Sw. A genus of "Hyrianæ," Sw. described as differing from HYRIA, Auct. in having a cardinal as well as a lateral tooth in each valve. Sw. p. 380.

HISTRIX. Humph. RICINULA, Auct.

JANERA. Schum. A genus composed of species of Pecten, Auct. having oblique plicæ or calli on each side of the ligamentary pit. _Ex._ P. plica, fig. 172. Decadopecten, Rüppell.

JANTHINA. Auct. (_Janthum_, a violet.) _Fam._ Neritacea, Lam. Oxystomata, Bl.--_Descr._ Sub-globose, thin, fragile; spire short, consisting of few whorls; aperture angulated, at the anterior junction of the inner and outer lips; columella tortuous, contiguous to the axis; outer lip thin, sinuated in the centre.--_Obs._ The shells composing this genus are celebrated for their beautiful purple colour. The animal possesses a small vesicular process, which keeps it floating on the surface of the water; it exudes a purple secretion when irritated. It is occasionally floated on to the shores of most temperate and tropical countries. Fig. 333, J. Fragilis.

JATARONUS. Adanson. CHAMA, Auct.

IBERUS. Montf. CAROCOLLA, Lam.

IBLA. Leach. _Fam._ Pedunculated Cirripedes, Lam.--_Descr._ Four valves, posterior pair elongated, anterior pair short, triangular; pedicle cylindrical, contracted at the base, hairy.--_Obs._ I. Cuveriana (fig. 40) is brought from Kangaroo Island.

ICTHYOSARCOLITES. Desmarest. _Fam._ Ammonacea, Lam.--_Descr._ Chambered, slightly arcuate, laterally compressed; septa simple, leaving triangular articulations imbricated like the thick muscles of a fish.

JESITES. Montf. A minute fossil resembling GALEOLARIA.

ILOTES. Montf. ORBICULINA, Bl. A genus of microscopic Foraminifera.

IMBRICARIA. Schum. CONOHELIX, Sw.

IMBRICATED. (_Imbrex_, a tile.) A shell is said to be imbricated when the superficial laminæ are arranged over each other in the manner of tiles.

IMPERATOR. Montf. A genus composed of species of the genus TROCHUS, Auct. with whorls angulated and stellated, having an umbilicus. _Ex._ T. Imperialis. Some of the shells named Imperator in the British Museum belong to the genus Calcar, Montf. having no umbilicus.

IMPRESSION. See MUSCULAR IMPRESSION.

INCRASSATED. (_Crassus_, thick.) Thickened, as the hinge of Glycimeris, fig. 67.

INCURVED. Turned inwards or bent forwards. Applied to symmetrical shells, when the point of the apex turns towards the anterior extremity, as in Patella. The apex of a shell is said to be incurved when it is bent inwards, but not sufficiently so to be described as spiral. _Ex._ Ammonoceras, Lam. fig. 477.

INDENTED. (_In_, in; _dens_, a tooth.) Exactly the reverse of DENTATED; meaning a series of small cavities, such as might be produced by the entrance of teeth. The cast of a dentated surface would be indented.

INEQUILATERAL. (_Æquus_, equal; _latus_, a side.) A term applied to a 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.

IO. 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.