350 PROCEEDINGS OF THE NATIONAL MUSEUM. 



This is Ctmeus Megerle, 1811, not of Da Costa, 1776; and Meroe 

 Schumacher, 1817. 



Section Solanderina Dall, 1902. Type, S. solandri Gray. 



Shell inflated, smooth, subequilateral. 



Section Sunetthta Jousseaume, 1901. Type, S. sunettlna Jousseaume, 

 8. memtrualis Menke, etc. 



Shell suborbicular, compressed, smooth. 



Genus GAFRARIUM Bolten, 1798. 



Type (by elimination), Venim j^ectinata Linn{eus. 



Shell equivalve, subequilateral, with a simple or sliohtl}^ sinuous 

 pallial line; three cardinals in each valve, entire or faintly grooved, 

 and the usual anterior laterals; surface sculptured. Tertiary and 

 recent warm seas of the Old World. 



Section Gafrarium Bolten, s. s. 



Surface with strong, chieflv radial, more or less dichotomous sculp- 

 ture, that of the posterior slope difl:ering- from the rest; valves 

 moderately convex, umbones subcompressed with a narrow lunule and 

 feebly defined escutcheon; pallial line simple, inner margins of the 

 valves crenate, the ligament sunken but not immersed; middle left 

 cardinal feebly grooved. 



This is Papli'ia Oken, 1815, not Bolten, 1798, or Lamarck, 1801; 

 Crtsta Romer, 1857; and Circe^ species, of many authors. 



? Section Badioonsta Dall, 1902. Type, Ventts pidcherrima Deshayes, 

 Journ. de Conchy]., VIII, 1860, p. 381, pi. xiv, figs. 1, 2. Tertiary. 



Shell with the form of ChioneJla the disk and anterior part ele- 

 gantly, regularly, concentrically sulcate; margins of the dorsal area 

 behind separated from the sulcate area by strong radial ril)bing; the 

 lunule not definitely circumscribed, but with its margins thickened and 

 surface concentrically striated or smooth; escutcheon elongate-ovate, 

 equally parted l)etween the valves, nearly smooth. Interior^ 



The horizon and internal characters of this remarkable fossil are 

 unknown, but it is provisionall}' located here, pending further 

 information. 



Section Gould/a C. B. Adams, 1847. Type, Thetis cerina Adams. 



Shell small, reticulately sculptured, the radials toward the ends of 

 the valves, and the concentri(^ sculpture in the middle of the disk 

 stronger; there is no specialized posterior area; moderately convex, 

 the umbones not compressed; pallial line slightly flexuous behind, 

 cardinals and inner margins of the valves entire. 



Warm-temperate and tropical seas. 



This group is Thetis C. B. Adams, 1845, not of Oken, 1815, or 

 Sowerby, 1826. It is not Gouldia Bonaparte {aves)^ 1850. It is the 

 only representative of the Gafrariuin or Circe group in American 

 Tertiary or recent seas, and has not yet been found on the Pacific 

 coast. 



