34 PROCEEDINGS OF THE NATIONAL MUSEUM Vol.70 



CTCLOSTREMELLA CONCORDIA Bartsch 



Plate 6, figs. 4, 5, 6 



Clclosti-emella concordia Baetsch, Journ, Wash. Acad. Sci., vol. 10, 1920, 

 No. 20, p. 572. 



Shell very small, planorboid, hyaline, semitransparent. Early 

 whorls eroded in all the specimens seen. The last two whorls curve 

 suddenly to the deeply channeled suture on the upper surface; the 

 rest gradually, evenly rounded. Periphery of the last whorl well 

 rounded. Base openly umbilicated. The entire surface of the 

 spire and base is marked by rather strong, irregularly developed 

 incremental lines and more or less equal and equally spaced, fine 

 spiral lirations. The intersections of these two sculptural elements 

 give to the surface of the shell the characteristic beaded sculpture 

 of the genus. Aperture very broadly ovate, almost subcircular, the 

 narrower portion being at the posterior angle; peristome thin, not 

 reflected; parietal wall covered by a thin callus. Operculum thin, 

 corneous, paucispiral. 



The type. Cat. No. 340862, U.S.N.M., was collected by Prof. Carl 

 C. Engberg at Olga, Washington, and measures, altitude, 1 mm.; 

 diameter, 2 mm. Two additional specimens from the same locality 

 are in Professor Engberg's collection. Cat. No. 342327, U.S.N.M., 

 contains two specimens collected at Lisabeula, Washington, by Pro- 

 fessor Engberg. Five more specimens from this locality are in the 

 Engberg collection. The Museum also has specimens from Friday 

 Harbor, Washington. 



This species has been known from the last-named locality under 

 the names of Skenia and Skeniopsis planorbis Fabricius. 



It is easily distinguished from its nearest neighbor, Cyclostremella 

 California Bartsch, by its smaller size, more robust form and weaker 

 sculpture. 



EXPLANATION OF PLATES 



Plate 1 



Fig. 1. Turl)onilla (Pyrgolampros) Ufa. 



2. Aclis calif ornica. 



3. Turionilla {Strioturhonilla) kincaidi. 



4. Turtonilla (Ohemniteia) eng'bergi. 



5. Astyris clementensis. 



6. Melanella {Melanella) portlandica. 



7. Turhonilla (Ptycheulimela) magdalenensis. 



8. Opalia tremperi. 



