HELCION-PATIXA. 113 



21. Inner lateral tooth, from the side. 



23. Outer lateral tooth and side cusp, from the inner side. 



24. The same, from the outer side. 



25. The same, from the posterior side. 



26. The three uncini. 



P. PRUINOSA Krauss. PI. 51, figs. 11, 11 ; pi. 13, figs. 68, 69. 



Shell oval, depressed-conical, nearly smooth, the apex near the 

 front fourth of the length. Surface having faint radiating stride. 

 Color varying from yellowish-olive to blackish-olive often mottled or 

 rayed, and having fine interrupted radiating lines of blue. Interior 

 olivaceous, dusky-whitish in the cavity. 



Length 28, breadth 21, alt. 6 mill. 



Length 31, breadth 24, alt. 9 mill. 



Cape Good Hope. 



P. pruinosa KRAUSS, Die Siidafric. Moll., p. 56, t. 3, f. 9. REEVE, 

 Conch. Icon., f. 109. Patinastra pruinosa THIELE, Das Gebiss der 

 Schn. ii, p. 326, t. 28, f. 24, 25 (dentition and jaw.) 



It is larger and more depressed than P. pellucida. The blue lines 

 are broken into minute dots. It has the same indistinct radiating 

 striae that are to be seen on the European species. 



Dr. Thiele has made this the type of a new genus, Patinastra, 

 founded upon a very slight difference in the dentition, which is inter- 

 mediate between that of Patina and Helcion. 



** * 



P. ROSEA Dall. PI. 50, fig. 44. 



Shell small, egg-ovate, of a deep rose color ; externally smooth 

 except for very faint radiating ridges divaricating from the apex, and 

 for lines of growth. Margin entire ; apex minute, produced before 

 the anterior margin. Interior smooth, white except the margins, 

 which are polished and of the same color as the exterior. Nacre, 

 especially when weathered, silvery. Length '35, width *27, alt. '12 

 inch, of largest specimen. (Dall.} 



East side of Simeonoff Island, Shumagins> 



Nacella (.*) rosea DALL, Proc. Cal. Acad, Sci. iv, p. 270, t. 1, f. 2 

 (Oct. 8, 1872.) 



The soft parts have not been examined. The position of this shell 

 in Nacella where originally placed, is therefore, doubtful. It may 



8 



