SP EC IES.
L H. albolabris. Shell thin, fragile ; convex, imperforated ; with six volutions, whorls obtusely wrinkled across, and spi rally striated with very fine impressed lines, a little waved by passing over the wrinkles, both becoming extinct to wards the apex, which is perfectly smooth ; aperture inflated, not angulated at the base of the column, but obtusely curved, lip contracting the mouth abrupt. ly, widely reflected, flat and white.
Length of the column, three-fifths ol an inch ; breadth one inch.
Plate 1. fig. 1.
Lister conch. tab. 47 ? Rhodia Ginelin's Edit. Slid. Xat.
The common garden snail, frequenting moist shaded situations, and is general!) well known. It is very probable this is the Rhodia of authors, but as in the des• cription of that species nothing is men tioned of the reflected lip, and not hay ing in our possession the vol. of Chemn conch. refeued to for a figure of it, we have made an interrogative reference and for the present have adopted a nets name.
2. H. arboreus. Shell very thin, fra gile, depressed, horn colour, pellucid very little convex ; whorls four, irregu larly wrinkled across ; aperture sublunat ed, lip thin, brittle, junction with the body whorl acute ; umbilicus large am deep.
Length one-tenth of an inch nearly breadth nearly one-fifth.
Plate 4. fig. 4.
Under the bark of decaying trees yen) common. Inhabitant pellucid ; base white acute behind, not extended forward be fore the head ; head and neck dusky tentacula four ; lower ones very short eyes placed in the tip of the superior pair.
The application of the Goniometer, up on some commodious construction, might very much facilitate the investigation and determination of species, by ascertaining the precise angle subtended by the two sides of the spire in univalves. This an gle combined with the length and breadth of the shell, and proportionate length of the mouth, would, it is conceived, give us a better idea of form, than we can have by the present mode of description ; it is a plan we have adopted in describing our marine shells.
3. H. Tridentata. Shell depressed, spire very little raised, brownish or horn colour ; whorls five, crossed by nume rous raised equidistant acute lines, sepa rated by regular grooves ; aperture lu nate, three-toothed ; teeth placed trian gularly, one on the pillar lip situated diagonally ; outer lip, abruptly contract ing the aperture, widely reflected and white, furnished with two of the teeth resembling projecting angles. Umbilicus moderate.
Half an inch wide.
Inhabits the middle states.
Plate 2. fig. 1.
Cochlea parva, nmbilicata, tenuiter stria ta, Tridens. sc. in triangulo positi, nempe unus ad fundum orbs, alter ad columellam, tertius ad labrum. Lister. Conch. tab. 92. fig. 92.
The three curves formed by the two teeth in the outer lip of this shell bear considerable resemblance to the orna ment often placed upon pannels in gothic architecture. It is found under the loose moist bark of decaying trees in some plenty.
Belongs to the genus Polydontes, Montf.
As many of the compound terms as possible ought to be banished from the language of Natural History, we would therefore propose, that the terms outer lip and pillar lip be substituted by Labrum and Labium; these would be equally expressive, and occupy less space in a de scription.
4. II. Alternata. Shell somewhat con vex, fuscus varied or alternating with pale rays ; whorls five, striated across with raised equidistant acute lines, forming grooves between them. Aperture thin and brittle ; lip regularly curved, within glossed with perlaceous, and placed before the light the fuscus lines appear sanguineous. Umbilicus large, exhibiting all the volutions.
Three-fourths of an inch wide. Inhabits the middle states.
Plate 1. fig. 2.
H. Radiate Gmelin's Etat. of Syst. Nat. p. 3634.
Cochlea umbilicata fusca, sive variegata capillaribus strys leviter exasperate. Lister. Conch. tab. 70, fig. 69.