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697 



TERTIARY FAUNA OF FLORIDA 



closely allied group with P. pcsfelis L. as the type; and Bucquoy, Dautzen- 

 berg, and Dollfus (1889) propose Peplinn, with P. clavaius Poll as type, which 

 would include such species as P. panauiensis ; and Sacco adds Flexopecteii 

 (1897) for P. flc.riiosiis Poli, which differs by having larger ears. 



Subgenus Psciidanntsudii H. and A. Adams, 1858. Tj^pe Pecten exoticns 

 C\\emn., = P. psc?ida?nusiuin (Klein) Sby. 



Shells small, thin, more or less translucent; the sculpture, if any, feeble; 

 inner face of the disk without lirse; disk with or without Camptonectes stria- 

 tion, frequently with concentric imbrication. 



Section Pseiidavnisium s. s. Type P. psejidanmshim Sby. (= exoticns Chemn., 

 etc.). 



Sculpture discrepant on the two valves, the right valve having the con- 

 centric, and the left valve the radial elements most pronounced ; valves usually 

 flattish or compressed. The type is a shallow-water species and shows bright 

 colors ; the species from deep water are frequently pale or whitish. The latter 

 have been separated as Cyclopccten by Verrill. 



Section Camptonectes (Agassiz MS.) Meek, 1864. Type P. lens Sby. 



Shell similarly sculptured on both valves, more or less inflated ; smooth, con- 

 centrically more or less undulated, divaricately striate, or delicately imbricated. 



The minute features of surface sculpture are so interchangeable and so 

 variable that I cannot regard them as having sectional, much less generic, 

 value, at least in the sense in which the term is used in this work.* 



Though Camptonectes was originally based on the character of the 

 divaricate strije, the species in which this character is obsolete must be 

 included, unless violence is to be done to what seems close relationship. 

 Syncyclonenia Meek, if correctly made out by that careful author, has a com- 

 pletely closed shell without a byssal notch, the ears subequal, the left valve 

 smooth, the right concentrically striated. 



* Professor Verrill proposes for the smooth form Pedinella ; for the undulaled form Hyalopecteii ; 

 the divaricately sculptured shells would then be typical Catnptonecles ; the imbricated ones like P. 

 vitreiis [(Gmelin, 1792) Dillwyn, 1817 (-|- aculeatus Jeffr., 1843, -|- abyssortiin Lovdn, -\- getnellaro-filii 

 Biondi) not P. vitrens Gray, 1824 (= P. gronlandicus Sby., 1843) ; P. vitreus Risso, 1826 ; P. vitreus 

 King, 1S31 (= P. cornens Sby., 1843), nor P. vitreus Sby., 1843] would be Palliolum Monts. 

 (restr.), 1884. Eburneopecten Conrad, 1865, based on P. scintillatus Conr., is an exact synonyme of 

 Camptonectes. Lissochlamis Sacco (1S97) is founded on P. excisus Bronn (non Pusch), a species 

 unknown to me. 



