Bulimia. A globular. oval, or turricu lated shell, the opening of which is en tire, not grooved at the base, and always longer than wide This genus of Brit gulere comprises some of the shells con sidered by Linnzus as Helices and Bullx; and the genera Auricida, Pyramidella, Melanis, Lymnza, Agathina, Maillot, and Bulima, of Lamarck. The essential cha racter distinguishing this genus from He lix is the opening being longer than it is wide.
Turbo. A conoidal or turriculated shell ; the opening entire, round, without any tooth ; the edges disjoined on the superior part. Several shells, which were reckoned by Lintreus of this genus, have been removed from it by Bru gulere, and placed under his genus Bulima, and others have been taken from it by Lamarck, and disposed un der the genera Cyclostoma and Turri tella.
Tmchus. A conical univalve shell : the opening almost always quadrangular flattened transversely ; the columella ob lique. Lamarck has divided this genus into four : 1. Trochus. 2. Solarium, with an open umbilicus, or crenelated opening on the inside of the spiral turn ings, as in the Trochus perspectives.
3. Monodenta. The opening rounded, and furnished with a tooth, formed by the truncated and projecting base of the columella, as in Trochus 'Rhin, Linnzus.
4. Pyramidella : the columella project. ing, perforated at its base, and possessing three transverse folds, as in Trochus do labratus, Linnzus.
Cerithium. A univalve turriculated shell, the opening terminated at its base by a short, narrow canal, either suddenly turning backwards or truncated, but never grooved out. In this genus of Brugulere are comprehended several shells from the genera Trochus, Strom bus, and Murex of Linnms. The shells differ from those of the Murex by their turriculated form ; and from the screws, in not having the groove at the base of the canal.
Pyrula. A subpyriform shell, canali culated at its base ; without any projec tions, and having the belly part nearer to its summit than to its base ; the spire short ; the columella smooth ; the right edge without a groove Lamarck, found ing the distinction on the situation of the bellied part of the shell, and on the greater or less length of the spire, has formed two new genera ; one with those shells possessing this character of the genus Bulls, and the other of the genus Murex, calling the former Pyrula, and the latter Fusus.
Murex An oval or elongated univalve shell, generally foliated, plaited, spinnus, or tuberculated ; the opening always prolonged into a canal, running straight, or turning directly backwards, and al ways entire. In the earlier stages of their growth it is difficult to separate the Murices from the Stromhi. Lamarck di vides this genus of Linnzus into five ge nera. 1. Murex, with tuberculated or spinous projections, and channelled at the base, as M. ramosus. 2. Fusus; fu siform, without projections, with the bel lied part either equally distant from the extremities or nearest to the base: spire elongated; columella smooth ; right edge without groove, as M. coign. 3. Fas ciolaria ; nearly fusiform ; no projections; with two or three very oblique folds on the columella : and channelled at the base, as in M. tulips. 4. fusiform or turriculated, without projec tions, and having a groove, or sinus, near the summit of the right edge, as in M. baby lonicus. 5 Cerithium, already de scribed.
Rostellaria. Lamarck has formed this genus on Strombus fitsus (Linnzits,) and on some fossil species found at Cutirtag non. The characters of the genus are : a fusiform shell, terminating inferiorly by a canal with a pointed beak ; the right edge entire or dentated ; dilated more or less in a wing, according to age, and having a sinus contiguous to the canal.
Strombus. A bellied univalve, termi nating, at its base, by a canal, accompa nied with a distinct sinus; the right lip dilating, or spreading itself nut, with age, in a simple or digitated lobe Lamarck divides the genus Strombus of Linnaeus into three. 1. Stromhus ; terminating in a short canal, truncated or grooved out; the right edge dilating, with age, into a simple entire wing or lobe ; with a sinus distinct from the groove at the base, as in S. pugilis. 2 Pterocera ; a bellied shell, terminated inferiorly by an elongated cit. nal ; the right edge dilating, with age, into a digitated wing, and having a sinus near its base, as in S. Iambus. 3. RosteUatia, the genus last described.