164 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.58. 



SYNCERA PANAMENSIS, new species. 



Plate 12, fig. 8. 



Shell large, elongate conic, bluish-white, the tip pale horn colored. 

 Nuclear whorls smooth, not differentiated from the succeeding turns. 

 Postnuclear whorls moderately rounded, appressed at the summit, 

 marked by rather strong, irregidarly spaced, retractively slanting 

 incremental lines and exceedingly fine microscopic spiral striations. 

 Suture feebly impressed. Periphery of the last whorl rather inflated, 

 obscurely angulated. Base rather long, with a feeble umbilical chink, 

 marked like the spire. Aperture large, oval ; posterior angle almost 

 acute; outer lip thick within, thin at the edge; inner lip strongly 

 curved and vei'y strongly reflected, continuing at the insertion into 

 a strong parietal callus, which renders the peritreme complete. Oper- 

 culum typical. 



The type and another specimen, Cat. No. 150870, U.S.N.M., come 

 from Panama. The type has seven and one-half whorls and meas- 

 ures — length, 6.2 mm.; diameter, 3 mm. 



SYNCERA MAGDALENENSIS, new species. 



Plate 12, fig. 5. 



Shell very small, elongate ovate, chestnut brown. Nuclear whorls 

 not differentiated from the postnuclear turns, well rounded. Post- 

 nuclear whorls strongly rounded, very narrowly shouldered at the 

 summit, marked by decidedly retractively curved axial lines of 

 growth and apparently without spiral markings. Suture strongly 

 marked. Periphery of the last whorl somewhat inflated, well 

 rounded. Base short, well rounded, with a very narrow umbilical 

 chink. Aperture very broadly oval ; posterior angle obtuse ; outer 

 lip thin; inner lip strongly curved, passing into the strong parietal 

 callus, which renders the peritreme complete. Operculum typical. 



The type, Cat. No. 218323, U.S.N.M., comes from Magdalena 

 Bay. It has 5.1 whorls and measures — altitude, 2.2 mm. ; diameter, 

 1.4 mm. Two additional lots have been examined, as follows: Cat. 

 No. 218325, U.S.N.M. seven specimens, from Magdalena Bay, Lower 

 California, and Cat. No. 218324, U.S.N.M., four specimens from the 

 same locality. 



SYNCERA TRANSLUCENS (Carpenter). 

 Plate 12, fig. 7. 



1864. Jeffreysia translucens Carpenter, Rept. Brit. Ass. Adv. Sci., 186.3, 

 pp. 613, 657. 



1865. Hydrobia eaUfornica Tryon, Araer. Journ. Conch., vol. 1, p. 221, pi. 

 22, fig. 11. 



1866. Jeffreysia translucens Carpenter, Proc. California Acad. Sci., vol. 3, 

 p. 219. 



Shell broadly ovate, light brown. Nuclear whorls not differentiated 

 from the remaining turns, well rounded. Postnuclear whorls 



