88 ZOOLOGY. 



wliicli it differs from tlie next family), and prolonged in a siphon, which 

 extends a little beyond the shell. The animal is carnivorous, and the tongue 

 is armed with hooked teeth. 



Fam. 10. CyprceidcB (or Involuta). In this flimily there is neither 

 operculum nor periostraca, the shell is rolled upon itself nearly as in Conus, 

 but some are rolled upon a cylindrical instead of a conical axis, so that there 

 is no spire exposed. The shells are very beautiful and highly polished, the 

 mantle being so wide that its sides can be turned over the back of the shell, 

 where it secretes the ornamental layer of the shell. The point of union of 

 the maro-ins of the mantle is often indicated by a discolored line upon the 

 back of the shell. 



C'yjmm (0. moneta, j)!. 76, jig. 5 ; C. mauritiana^ fig. 6 ; C. arabica., 

 fig. 7), has the mantle edged with tentacular filaments, and when they are 

 turned over the back, the shell is hidden. The aperture is long and narrow, 

 each side denticulated, and the external margin turned in. C. moneta is 

 used as money in western Africa. 



Ovula (0. ovu77i,^l. 76, fig. 4 ; 0. volva,fig. 2), as the name indicates, is 

 shaped somewhat like an egg, with the ends attenuated, and the inner 

 margin of the aperture without denticulations. The animal resembles tliat 

 of Cypraja. 



Oliva {0. ispidula, ])} . 75, fig. 122 ; O.jyorjyJiyria, fig. 125 ; 0. maura, 

 fig. 126) has the head very small, and the tentacles united at the base. 

 These resemble somewhat the same organs in Strombus, being divided, and 

 having a terminal eye upon one of the branches. O. porphyria is the 

 largest and handsomest sj)ecies of the genus, being four or more inches long, 

 of a pale brownish purple, marked with numerous zigzag angular lines, and 

 having the anterior extremity violet. It inhabits the coast of South America. 



Fam. 11. YolutidcB. In this carnivorous family there are usually distinct 

 folds upon the columella. Yoluta is a genus of large and handsome, generally 

 inoperculate shells, with a wide aperture notched in front, and the apex 

 rounded. A part of the shell has sometimes the appearance of being 

 varnished, which indicates the extent to which it is covered by the mantle. 

 The animal cannot entirely enter the shell, the head is proboscidiform, and 

 the tentacles are short, with the eyes at their external base. 



Mitra {M. episcojpalis, j)l- 7^, fig. 123; M. i^apalis, fig. 124) is a genus 

 of handsome shells extremely rich in species, there being about 250 recent 

 and 100 fossil species known. The animal is very dull in its movements, 

 the head small and V-shaped, on account of the projection of the slender 

 tentacles. These have thie eyes upon an external peduncle. In Mitra 

 episcopalis (shell white with red spots), the rostrum is once and a half 

 times the length of the shell, exceeding that of any other genus. This 

 enables it to attack its prey at some distance. 



Terehra {T. maculata, i)l. 75, fig. 117) has the foot (which bears an 

 operculum) but little longer than the last whirl of the shell, a proboscidiform 

 head, tentacles and eyes in the usual form, and the siphon projecting beyond 

 the shell. There are upwards of a hundred recent species known. 



Fam. 12. Sigaretidce. Sigaretus {S. haliotideus, pi. 75, fig. 89) is a 

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