438 SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL. 50 



approached, sculpture consisting of numerous fine incremental lines, 

 some of which are more prominent than the great majority, these 

 more prominent ones giving a slightly irregular surface to the shell. 

 Hinge and interior unknown, but probably quite similar to S. hemp- 

 hilli. 



Dimensions. — Longitude, 120 mm.; altitude, 85 mm.; diameter, 

 59 mm. 



Notes. — This species is near S. hemphilli Dall, but is constantly 

 and decidedly narrower. Named for Sisquoc, near the type locality. 



Type.— Cat. No. 165,292, U. S. N. M. 



Locality. — Alcatraz asphalt mine, near Sisquoc, Santa Barbara 

 County, California; locality No. 4471. 



Horizon. — Fernando formation, lower Pliocene portion. 



MITRAMORPHA FILOSA Carpenter, var. BARBARENSIS, new 



variety 



PI. LVII, fig. I 



Description. — Shell averaging between 6 and 7 millimeters in 

 length, mitraform ; apex quite acute. Whorls six, slightly ventricose, 

 angulated above at suture ; two nuclear whorls, smooth and some- 

 what irregular, the second being eccentric with relation to the axis 

 of the spire ; other whorls ornamented by four rounded, raised, 

 revolving ridges and (16 on the penultimate whorl of the type) 

 rounded longitudinal ribs. The longitudinal sculpture is relatively 

 of greater prominence on the upper whorls and fades away below the 

 middle of the body whorl. In the type the body whorl is sculptured 

 by 16 revolving lines, those toward the base being faint. Suture 

 appressed, distinct. Aperture narrow, and elliptical ; canal short. 

 Outer lip smooth, inner lip slightly reflexed toward base, columella 

 showing faint indications of two plications, lower part of columella 

 showing trace of axial sculpture. 



Dimensions. — Altitude, 6.5 mm.; latitude, 2.6 mm.; altitude of 

 aperture and canal, together, 3 mm. ; latitude of aperture, 1 mm. 



No.TES. — In this variety the whorls are more convex, the longi- 

 tudinal sculpture much more pronounced, the suture more distinct, 

 and the canal relatively narrower than in the type. It lies between 

 M. Hlosa and M. intermedia Arnold, having more numerous and less 

 prominent longitudinal ribs than the latter. Recent specimens of 

 a variety of M. filosa very closely resembling var. barbarensis are in 

 the National Museum labeled from Monterey. It is the opinion of 

 the writer that the prominently longitudinally sculptured forms are 

 northern types inhabiting somewhat colder water than the typical 

 filosa. 



