OP CONCHOLOGY. 7 



There is no recent or fossil species of Palliuvi in America, 

 the type of that genus living on the shores of the Mauritius and 

 Phillippine Islands. The genus Dentopecten, Rlippell, founded 

 on P. plica, Lin., is not the genus Pallium, Klein, as Shumacher 

 regards it-, but of Martini. 



Lyropecten is exclusively American, living within the tropics, 

 and found in a fossil state in California only ; much farther north 

 .than the localities of the recent species. 



Lyropecten intermedius, Conrad. 



Description. — Rounded-oval, ventricose ; ribs 9 — 10 nodose, 

 as wide as the interstices ; with numerous closely scaled striae 

 covering the whole surface, and numbering about ten between 

 each rib. Purple, within purple, with a large Avhite central de- 

 posit of callus. 



Length 4|, breadth 4| inches. 



Locality. — Cape St. Lucas, California. 

 Cabinet of the Academy of Natural Sciences. 



Observations. — This shell, of which a single, somewhat worn 

 valve is in our collection, was received by the Academy from 

 the Smithsonian Institution of Washington, with the following 

 label attached : 



'•'■ Pecten suhnodosus, var. intermedius.'' It differs from suh- 

 nodosus, however, in having much finer striae, numbering nearly 

 double as many between each rib. 



