Marginella glabrella. M. radiata. M. quinqueplicata. M. limbata. M. rosea. M. lifasciata. M. faba. M. dentifera. M. dactylus. M. bullata. M. cornea. M. avellana. M. nubeculata. M. cærulescens. M. aurantia. M. bivaricosa. M. longivaricosa. M. muscaria. M. eburnea. M. formicula. M. persicula. M. lineata. M. tessellata. M. interrupta. _M. lineata._ The lineated Marginella. Pl. 30, fig. 3. Species with aperture as long as the shell; spire not projecting, sometimes sunk or umbilicated. _M. faba._ The Bean Marginella. Species with aperture shorter than the shell, and the spire projecting. _M. cærulescens._ The cerulean Marginella. Species with surface bluish white; spire short and acute; four plaits on the columella; interior lip brownish purple. 5. Volvaria. Five species. The connecting genus between those shells that have a columella and those that are evolved upon their own axis. Distinguished from the Marginella by not having a thickened outer lip. The shells are marine, and generally very small. Shell cylindrical, convolute; spire obsolete or concealed; aperture narrow, the whole length of the shell, with one or more plaits on the columella at the lower part. Volvaria monilis. V. pallida. V. triticea. V. oryza. V. miliacea. _V. monilis._ The Necklace Volvaria. Pl. 29, fig. 5. Species greatly involuted; aperture very narrow and very long; plaits on the anterior part of the columellar edge; the exterior edge thin. FAMILY XX. CONVOLUTA. Six genera. 1. Ovula. The Egg. 12 species. This is the first genus of Lamarck’s arrangement of convoluted shells; it is nearly allied to the Cypræa, but easily distinguished from it by the want of spire, and by not having teeth on the columellar lip; the right lip is reflected inwardly, sometimes wrinkled and sometimes smooth. Shell oblong, convex, resembling the Cypræa in form, with the two extremities of the aperture notched, and more or less prolonged like a tube; the left margin dentated.