184 TURBINIXJE. 



The above I have copied from Philippi, who quotes from Gray. 

 I cannot find the original description. 



P. FLAVA Anton, 1839. 



'* Lang conoidisch oval, 6 flache Winduugen, die letzte f des 

 Gauzen, glatte, glanzend, blass isabellgelb, mit dunkelisabellgelben 

 vier-eckigen Flecken ; Spindel etwas abgestutzt, weiss ; ungenabelt ; 

 Mundung lang-oval." Alt. 5, diam. 2? lines. (Anton.) 



Habitat unknown. 



Subfamily TUKBININ^E. 



Shell turbinate or trochiform, solid, nacreous within, smooth or 

 sculptured outside ; operculum circular or elongated, smooth or rug- 

 ulose outside. Foot rather short and broad ; epipodial line with 

 or without cirrhi. Dentition always according to the formula 

 oo*5'l'5' QO. 



In this subfamily there are three well-marked groups, here con- 

 sidered to rank as genera, of perhaps nearly equal systematic value. 

 The principal characters upon which this division is based are the 

 operculum and the radula. The latter is discussed as fully as my 

 material permits below. The operculum, in the entire group, com- 

 mences as a multispiral disc, like that of a trochus, upon the outer 

 side of which is deposited a thin calcareous layer by a lobe of the 

 foot which projects partly over it. This arrangement produces an 

 operculum which exhibits all the whorls beneath, but which is only 

 feebly, or not obviously spiral above, from the more or less general 

 distribution of the calcareous matter. 



In the genus Leptotkyra the development does not go beyond the 

 primitive stage. The operculum is multispiral, with a thin, calca- 

 reous stratum, slightly more prominent around the outer whorl. In 

 Turbo the nucleus is the same ; but several more rapidly increasing 

 whorls are added, upon which a much heavier layer of calcareous 

 material, covering the whole surface, is deposited. In Astralium a 

 very rapidly enlarging whorl starts from the multispiral nucleus, 

 forming far the greater portion of the operculum, and usually leaving 

 a pit at the starting point. 



The radula is broad and generally rather short. Median, lateral 

 and marginal teeth are always present, and the formula is invariably 

 QO -5'1 '5- oo. The central teeth are always more developed than in 

 the Phasianellince, (in which the central tooth represents the part 

 here called the body.) but never have the long serrate cusps so 



