THE NAUTILUS. 



VOL. XXX. OCTOBER, 1916. No. 6 



A NEW SUBEMARGINULA FROM CALIFORNIA. ' 



BY WILLIAM HEALEY BALL. 



Among some specimens sent for examination from California 

 I find a new Subemarginula collected by Mrs. W. H. Golisch of 

 Los Angeles at San Nicolas island of the Santa Barbara group. 



SUBEMARGINULA GOLISCH.E n. sp. 



Shell of moderate size, radiately ribbed, concentrically zoned 

 and radiately striped with dark rose color, the worn apex green- 

 ish, the interior whitish, the extreme edge of the slightly cren- 

 ulated interior margin with the external coloration showing 

 through. Sculpture of rather strong radial ribs, corrugated 

 more or less by strong incremental rugosities, alternated in front 

 and behind with a single feebler rib, on the sides there are two 

 or three minor riblets between the major ribs ; apex rather 

 acute, somewhat anterior ; marginal notch shallow, its groove 

 distinct on the internal face of the shell ; the number of major 

 ribs in the type specimen is about twenty. Length 20 ; apex 

 behind the notch 7 ; width 13 ; height 7.5 mm. 



In a general way this shell looks like one of the varieties of 

 Fissurella volcano Reeve, except for the entire apex. 



OBSERVATIONS ON TTNIO GIGANTEUS BARNES. 



BY L. S. FRIERSON. 



Although the common and striking plicated shells were 

 among the first of the Western Unios to receive names, their 

 nomenclature is still considerably confused. 



