54 THE NAUTILUS. 



bb. umbilicus small, deep. 



c. lip thickened within, centervillensis Tryon. 



cc. lip simple, thin. 



d. whorls angular above the middle, dilatatus Gld. 

 dd. whorls rounded or angular below the middle. 

 e. spire sunken in center, deflect us Say. 



ee. spire level, apex not sunken. 



umbilicatellus Ckll. 



Planorbis callioglyptus n. sp. 



Shell thin, yellowish corneous. Upper side flat, only a trifle con- 

 cave in the middle; lower side convex ; periphery very bluntly in- 

 distinctly angular, and midway between periphery and suture there 

 is a slight angle; but both angles are obsolete at aperture; base 

 often spirally malleated. Surface with a beautiful sculpture of fine 

 spiral incised lines, crenulated by fine growth-lines. Whorls nearly 

 4. Umbilicus nearly a third the shell's diameter, deep and funnel- 

 shaped, its edge bluntly angular. Aperture ovate truncate, mod- 

 erately oblique. Lip not thickened inside. Alt. 3, diam. 8 mm. 



Freeport, Washington, collected by H. Hemphill. 



Planorbis opercularis var. oregonensis n. v. 



Shell light yellowish, opaque. Upper surface flattened, slightly 

 convex, the apex sunken ; periphery keeled with a slight groove 

 above the keel. Surface finely spirally striated. Umbilicus rather 

 small and deep, its edge slightly angular. Aperture approaching 

 vertical, lip thiekenad within. Alt. 2, diam. 6 mm. 



Salem and Portland, Oregon. This looks very much like typical 

 opercularis, but may be distinguished by the beautiful spiral sculp- 

 ture and thickening within the lip. It differs from calliogli/ptus in 

 having a decided keel around the nearly flat upper surface and a 

 distinct thickening within the aperture. I have not seen any typical 

 P. opercularis from Oregon. There are none in the collection of 

 the Academy of Natural Sciences. 



SYNONYM.-;. 



/'. lii/lini/.tii Lea =pari'its Say. 



P. broif it iartiana Lea exacutus Say. 



P. buclianensis Lea = exu<-nh<* S:iy ( fide Simpson). 



P. dreunistriatiis Tryon pifrrux Sav. 



P. co urn i' us Auth.,M. S. parvtts Say. 



/'. fuaintiiK DeTarrit Reecher= /'. mint I /m* var. cn'staiua Drap. 



