PHASIANELLID^. 303 



from the elongfilcd species of Trochidse by the calcareous 

 operculum. 



Phasianella, Lam. 



Pheasant-shell. 



Distr. — 25 sp. Australia, large species ; India, Philippines, 

 small species; Mediterranean, Britain, West Indies, very small 

 species. Fossil, 70 sp. Devonian — ; Europe. P. buUmoides, 

 Lam. (Ixxix, 6). 



Shell elongated, polished, richly colored ; whorls convex ; 

 aperture oval, not pearly ; inner lip callous^outer thin. Oper- 

 culum shell}^, callous outside, subspiral inside. 



When the animals of this genus crawl, the foot appears to be 

 divided longitudinally into halves, which advance alternately ; 

 when the right side moves, the left remains stationary, and when 

 this in turn is carried forward, the other half remains as a point 

 of 'support ; it may be compared to the amble or canter of a 

 horse. In Phasianella proper, the tentacles are ciliated, the 

 head-lobes fringed, and the sides of the foot furnished with three 

 cirri. In the smaller species, forming the Tricolia of Risso, 

 the head-lobes appear to be wanting. The larger species, all of 

 which have beautifully variegated shells, are principally from 

 Australia, and the smaller ones from the Mediterranean, West 

 Indies and South Africa. 



TRICOLIA, Risso. (Eudora, Leach.) Shell thin, spire elevated, 

 apex mammillated ; suture profound ; aperture oval. Small 

 species, Mediterranean, etc. P. Niciensis, Risso ^^lxxix, T,. 

 P. pulla^ Linn. (Ixxix, 8). 



LEIOPYRGA, A. Ad. Shell turbinate, thin, smooth, polished ; 

 aperture semicircular, shorter than the spire, inner lip thin, colu- 

 mella incurved, excavated, P. picturata, A. Ad. 



EUCOSMiA, Carp. Shell small, turbinate, solid, smooth, varie- 

 gated, not nacreous ; aperture with the margins nearly contin- 

 uous, but not callous ; columella slightly excavated ; axis 

 umbilicated. 6 sp. West Coast of N. America, P. variegata, 

 Carp. 



Alcyna, a. Adams. 



Distr. — 2 sp. Japan. A. rubra, Pease. 



Shell acuminately ovate, imperforate, spire short, conical, 

 acute ; whorls liat, smooth ; aperture oval ; inner lip callous, 

 terminating in a strong tooth below ; outer lip acute, smooth 

 within. 



Chromotis, a. Ad. 



Distr. — Phas.neritina, Dunker (Ixxix, 9). Cape of Good Hope. 



Shell ear-shaped, thin, polished ; spire veiy short; whorls few, 

 rapidly enlarging; aperture oval, columella flattened and solid. 

 Operculum calcareous. 



