. Elements of conchology / Prepared for the use of schools and colleges. Mollusks. AH have the aperture of the shell very narrow {fg. 66), a disposition approaching to the characteristic of the following tribe. 14. In the Tribe of Angiostoma, the aperture is generally so narrow that, to enter it, the foot of the animal is obliged to be doubled. In some, designated under the com- mon name of Volutes—Voluta—the aperture, which is of various forms, is terminated by a notch without a canal, and the columella is marked by oblique, projecting plicfe (folds), {fig. 67) : they are sub- divided into Vo
. Elements of conchology / Prepared for the use of schools and colleges. Mollusks. AH have the aperture of the shell very narrow {fg. 66), a disposition approaching to the characteristic of the following tribe. 14. In the Tribe of Angiostoma, the aperture is generally so narrow that, to enter it, the foot of the animal is obliged to be doubled. In some, designated under the com- mon name of Volutes—Voluta—the aperture, which is of various forms, is terminated by a notch without a canal, and the columella is marked by oblique, projecting plicfe (folds), {fig. 67) : they are sub- divided into Volutes proper {fg. 56,page ), in which the aperture is wide, and the columella is marked by some large plicse, and the last whorl of the spire is sometimes ventricose, some- times conical; in the Mitra the spire is in general pointed and elongated, and in Oliva, so called from the oblong or ellipsoid form of the shell, the aperture is long, narrow, and notched opposite to the spire, and the columella is marked by numerous plicae {fig. 67). 16. In others the shell is oval, the spire is concealed, and the aperture, which is long and narrow, has no plicse on the side of the columella, but presents a notch or canal at its two extremities; these are the OvuL^ (fg. 68). Fig. 67. Fig. 68. OVULA VOLVA. 17, In others again, the Cythjeje (Porcelana), the shell, which is protuberant in the middle, and almost as much con- 14. What is the peculiarity of the tribe of Angiostoma? (Angiostoma, Greek, aggeion, a vessel, and stoma, mouth.) 15. What are the characters of Volu'ta ? (Voluta, Latin, a wreath.) What is the character of Oli'va ? (Oliva, Latin, an olive.) 16. What are the characters of the genus O'vula ? (Ovula, from the Latin, ovum, an egg.) 17. What are the characters of the genus Cyprse'a ? (Cypraea, Latin, a Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of
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