"_C. helvola_, the star-cowry, has the sides dark orange; the fawn-coloured back studded with small spots. It comes from the Maldives. "_C. moneta_, the money-cowry, is generally white, sometimes yellow. [Sidenote: TÆREBELLUM. OLIVA. TRIVIA.] "_C. annulus_, the ring-cowry, has a yellow mark round the top of the shell. The fowl-cowry, _C. moneta_, is used for money by the natives of Siam and Bengal. "_C. pediculus_ is changed to _Trivia_, a new sub-genus from _Cypræa_. We find the following characters:--form of the columella internally concave, ribbed; shell sub-globular, cross-ribbed. _T. carnea_, flesh-coloured shell; thin, pure rose-coloured, with very thin, distant ribs; lips whitish: it has sometimes an indistinct dorsal groove. "_Trivia Europæa_ (_Cypræa_ of authors) is a globose shell, ash or flesh-coloured, with three black dots and a whitish dorsal streak; ribs close, rather thick, and whitish; base white; outer lip wide. The variety has the back without spots. _T. pediculus_ has six square dorsal spots; the colour of the shell pale red; ribs rather thick-covered; dorsal line narrow; base reddish. Only one species, _C. Europæa_ (or _Trivia_) is a native of our shores. "There are several fossil species of _Cypræa_. "We now pass on to a genus in which there is but one recent species, _Terebellum subulatum_, _Bulla_ of Linnæus. (See Frontispiece.) A fossil _Terebellum_ is found in London clay. [Sidenote: ANCILLA. CONUS.] "The _Oliva_ genus contains smooth, shining shells, common, and therefore little valued; nevertheless they are beautiful, and of various colours. "The columella is obliquely striated; the aperture longitudinal and straight. The olives were placed by Linnæus among the _Volutæ_, on account of the striæ on the columella, without regard to the peculiarity of the _canal_, by which the olives are known from all other shells. This canal separates the _volutions_ of _Oliva_. Many species are prettily marked by nature, others are rendered handsome by polishing. _O. subulata_ is small, and pointed like a mitre. The common olive is white, with brown, waved lines. _O. irrisans_ is ornamented with yellow zigzag lines: it has two brown zones. _O. oriza_, the little rice-olive, is white. "I should have noticed the small genus _Ancilla_, formerly _Ancillaria_, which is very near both to _Terebellum_ and _Oliva_. The columella has a varix at the base, which distinguishes it from _Terebellum_, and it wants the canal which separates the volutions of _Oliva_. "There are several fossil species. "The concluding genus of the third order is very large, and contains rare and costly shells. This is _Conus_, scarcely to be mistaken for any other genus except _Voluta_, and that only at a first glance. [Sidenote: CONUS.]