I'Ol.YTKOPA. 171 



i)inu})er of loniis to which different names have been attached. 

 These include P. rugoxa, Qnoy (fig. 112), which does not differ 

 much; F. fi'istis, Dunker (fig. 124), and /'. albomarginata, Desh. 

 (fig. 121 ), which is a depauperate state of Irisiis ; P. Quoyi, 

 Reeve (fig. 1 22), an extreme ribbed form, together with an inter- 

 mediate state figured hy Kiener and Kiister. 



Dr. Gould was the first (in Moll. Wilkes' Kxped. ) to notice the 

 variation from costate to smooth forms in the New Zealand 

 specimens, and the latter becomes usual in those from the Cape. 

 1 figure of these P. caiaracta, Reeve (fig. 132), as of Chemnitz, 

 F. lagenaria, Duclos (fig. 128), F. dubia, Krauss (fig. 127), P. 

 versicolor, ^'oo(\ (fig. 183), according to Kiister; the last con- 

 necting with the ribbed form. F. Zeyheri, Krauss, ai)pears to be 

 founded on m young shell. 



P. HARPA. Conr. ri. 52, fig. 145. 



Chocolate, the revolving ridges maculate with white; bluish 

 within, columella and lip-dentations tinged with chocolate, with 

 narrow revolving bands of the same color. Length, 1-1-25 inches. 



Finndwirh Isles . 



A rather constant species in sculpture and coloration, and ap- 

 parently of limited distribution. 



P. LAPiLLUs, Linn. 



iShell usually whitisli or orange-brown or chocolate-colored ; 

 with sometimes one to several white revolving bands. Obso- 

 letely ribbed, conspicuousl}' ribbed, or covered with revolving 

 strise ; surface smooth, or imbricated or lamellate by the crossing 

 of the growth-lines upon the revolving ribs. Lip at the rest 

 period in the adults usually much thickened within and dentate. 



Length, 1-2-5 inches. 

 Boreal Seas ; North Europe to North Africa {not Mediterranean) ; 



Northern Atlantic Shores of the United States to Greenland ; 



{Siberia to Japan ; BeliHng's Straits to California. ?) 



The quantity and variety of material before me, embracing a 

 rich series of forms from many localities, together with the com- 

 parison of the numerous descriptions and figures that have been 

 published, induce me to include under this, the oldest name, a 

 very large number of nominal species. As in the case of P. 

 hsemastoma, I have considered it preferable to retain some of 



