84 The Williams Collection of Shells 



from Central America, clearly demonstrate that oysters 

 are not to be despised, either for stature or looks. 

 The fossil genera Exogyra and Gryphaea are repre- 

 sented, as well as fossil species of Ostrea proper. 



Last but not least are the Pectinidae and Spon- 

 dylidae. There are over a hundred species of the 

 Pecten clan, representing the forms usually called 

 Pecten, Vola, Amussium and Hinnites, but which must 

 now be distributed under a number of new generic 

 designations. For richness of coloring and elaborate 

 simplicity of dress, no group of mollusc shells can sur- 

 pass the members of this family, unless it be the one 

 that immediately follows, before turning to which let us 

 note eight interesting accessions: Pecten dringi, Reeve, 

 from off Western Australia; an especially beautiful 

 P. plica, Linnaeus, from the Indian Ocean; a P. 

 reevei, Adams and Reeve; P. swifti, Bernard, from 

 Japan; P. diegensis, Dall, dredged in deep water in San 

 Pedro Bay; P. leopardus, Reeve, N. W. Australia; 

 the new P. keppelianus, Sowerby, from Cape Verde 

 Islands, and P. luculentus, Reeve, from Tahiti, — all 

 rare. Surely I have never seen and never expect to see 

 a more exquisite display of these particularly charming 

 forms. 



There are also many fossil Pectens sent by Mr. 

 Hemphill from the California Tertiary beds, of which 

 he says that it is seldom possible to get such perfect 

 specimens. 



