COMPLETE GRAU : PECTINIDAE OF THE EASTERN PACIFIC 127 



Ecological data: King (1831, p. 337) commented, "This shell is 

 found attached to the leaves of the Fucus giganteus, and with other 

 Alollusca, is the food of the Steamer or Race-horse Duck {Micropterus 

 brachyptera and M. Patagonica) ." Philippi, after his description of this 

 species, observed that it w^as abundant among "great masses of giant sea- 

 weed," either swimming about or attached, and seemed only to occur in 

 places "where the sea cannot possibly become turbulent." 



Genus NODIPEGTEN Dall 1898 



Nodipecten Dall, 1898, p. 695. [Proposed as a section of Chlamys.] 

 Type species: Ostrea nodosa Linne, 1758, p. 697. [Synonyms: 

 Pecten corallinus Chemnitz, 1784, p. 306, pi. 64, figs. 609-611; 

 Ostrea decemradiata Gmelin, 1791, p. 3329; Pecten fragosus 

 Conrad, 1849, p. 214, pi. 39, fig. 11 ; Pecten pernodosus Heilprin, 

 1887, p. 131, pi. 16b, figs. 69, 69a (Pliocene of Florida) ; Pecten 

 (Lyropecten) pittieri Dall, 1912, p. 10 (Pleistocene of Costa 

 Rica)]; type locality: "Habitat in O. Africano & Indico." Geo- 

 graphical range: western Atlantic, from North Carolina to Brazil 

 (about 15° south, possibly farther) ; Caribbean Sea and Gulf of 

 Mexico. Also reported from Canar}' Islands, west Africa and 

 Mauritius, but records very doubtful. 

 Original diagnosis: Shell like Lyropecten, but the ribs intermittently 

 nodose, with more or less prominent hollow nodes or bullae ; radial 

 striation pronounced ; ears unequal, the posterior smaller, the valves 

 often more or less oblique; imbricate surface layer sometimes very 

 marked. 



Additional diagnosis: Shell nearly equivalve, flatly to rather deeply 

 convex, slightly higher than long, and often moderately to sharply 

 compressed at ventral margin ; anterior auricles longer than posterior and 

 with prominent radial ridges ; byssus sinus moderately deep. Ribs strong, 

 with pronounced radial ridges and nodules, latter usually larger on left 

 valve and often present only on alternate ribs ; disk and auricles moder- 

 ately to profusely imbricated. Hinge dentition strong, diagonal linear 

 crura adjoining provinculum usually being quite prominent. 



Remarks: The locality Linne gave for the type species is obviously 

 incorrect. North (see Preface) examined the Pectinidae in Linne's 

 cabinet (Linnean Society, Burlington House, London), and said that 

 although the locality may indicate that he was referring to the shell now 

 known as Nodipecten corallinoides (d'Orbigny), Drawer 8 contains two 

 left valves of typical N. nodosus. 



