210 PROCEEDINGS OF THE ACADEMY OF [1894. 



une impression tres marquee, que borde une profoude depression en 

 fer u cheval. Le limbe est simple, epais. L'interieur est lisse, 

 blancbatre, avec le fond rougeatre. Sa i'nce superieure etait rougee 

 et couverte de tubes de serpules. 



" Nous ti'ouvames cette graude coquille jetee sur les rochers de 

 corail de I'ile de Borabora, dans I'arcbipel de la Societe. "* 



The dimensions given by Lesson, 5x7 inches, indicate a much more 

 oblong shell than any known specimens of kermadecensis, and the 

 coloring of the interior differs also. The difference in outline may 

 be most readily appreciated by plotting an ovate contour with the 

 axes 5x7 inches, and comparing with a contour of kennadecends. 



P. pica Reeve, if it is the same as P. kennadecensis, is a very 

 young specimen. The description and illustrations may be found in 

 Reeve's Conchologia Iconica, vol. viii, pi. xix, figs. 45 a-c. The 

 type, if still preserved, is in the British Museum, and should be 

 compared with young specimens of kermadecensis of the same size. 



The types of P. kermadecensis may be described as follows : — 



Shell large, thick and heavy ; round-ovate, slightly narrowed in 

 front, broadly rounded behind, conical, the apex central. Altitude 

 of cone nearly equal to half the breadth of the base, but decidedly 

 less than half the length; slopes straight. Surface dull and much 

 corroded by various parasitic growths, calcareous alga3, and young 

 Patellas, apparently of the same species, leaving but little of the 

 original sculpture, which seems to have consisted of numerous rather 

 low, radiating ribs, the interspaces and ribs covered with a secondary 

 sculpture of radial riblets. 



Interior whitish, more or less tinted with gray or dull reddish; 

 the muscle impression and the edge of the shell either white or deep 

 salmon colored. Border of shell slightly crenulated by tlie external 

 sculpture. Muscle-impression strongly marked, roughened, and 

 either impressed, or thickened and like a shelf or terrace. 



Dimensions of tAVO specimens: — 



Length 186, breadth 116, altitude 55 ram. 



119.5, " 104, " 50 " 



These siiells are decidedly more elevated than the examples in the 

 collection of Mr. Taylor, who writes as follows : — 



" My suite of kermadecensis consists of two full-grown shells and a 



' Voy. de lii Coquille, Zool., II, p. 423, 1830. Sec, also, /'. crassa Lesson, ibid., 

 p. 413, .said to be from New .South Wales. 



