236 CALIFOKNIA ACADEMY OF SCIENCES. 



226. Nassa versicolor C. B. Adams, var. hooveri, var. nov. 



Plate IV, Fig. 6. 



Nassa versicolor C. B. Ad., Panama Cat., p. 66, 1852. Tryon, Man. Conch., Vol. IV, p. 50, PI. XV, 

 figs. 270-272, 275, 1882. 



Shell small, conical; spire not highly elevated; apex subacute; whorls six, slightly convex, 

 crossed by fifteen prominent rounded ribs which bend slightly forward on the upper whorls, and are 

 abruptly truncated at the sutures; on the body-whorl these ribs are concave anteriorly and become 

 obsolete on the lower portion of the whorl; ribs on the upper whorls are of uniform size for their full 

 length; suture deeply impressed, distinct; spiral ornamentation consists of eleven to thirteen grooves, 

 which extend to base on body-whorl; columella extended, plication on inner side, and deep, narrow 

 groove around it at base of body-whorl; outer lip thickened by a prominent, smooth ridge on the 

 inner side; inner lip incrusted, the spiral sculpture, however, showing through the incrustation; 

 canal short, broad, with effuse lips. 



Di7nensio?is. — Long. 14.5 mm.; lat. 9 mm.; body-whorl 10 mm.; aperture, including canal, 

 7 mm. ; defl. 54 degrees. 



A unique form for this locality; somewhat resembles N. tegula in shape, but 

 easily distinguishable from that species by the sculpture. Pronounced a variety of 

 N. versicolor Adams, by Dr. Dall. N. versicolor is found in the southern fauna, its 

 habitat being Panama to Mazatlan according to Tryon. 



Rare in upper San Pedro series of San Pedro; two specimens found, one a 

 junior. The specimen figured is the type, which was obtained from the upper San 

 Pedro series of San Pedro, and is now in the United States National Museum. 



Pleistocene. — San Pedro (Arnold). 



Family LX. COLUMBELLID.E. 



Genus Columbella Lamarck. 



Shell strombiform or obovate, smooth or longitudinally or tranversely ribbed; internal lip 

 excavated in the middle, crenulated or denticulated; outer lip inflected and internally thickened and 

 Granulated in the middle. 



Columbella mercatoria Lara, is a characteristic species. 



227. Columbella solidula Reeve, var. praecursor, var. nov. 



Plate X, Fig. 4. 



Columbella solidula RvE., Conch. Icon., Vol. XI, PI. XXIV, fig. 149, 1859. Tryon, Man. Conch., 

 Vol. V, p. 147, PI. LII, figs. 92 and 93, 1883. 



Shell small, broadly fusiform; spire elevated; apex rounded; whorls seven, only slightly 

 convex, slightly shouldered above, smooth; body-whorl two-thirds length of shell, with row of nodes 

 on shoulder, each node being the termination of a faint transverse ridge which becomes obsolete on 

 lower portion of whorl; columella with spiral sulcations on exterior; aperture rhomboidal, narrow; 

 outer lip thickened internally by row of prominent teeth; inner lip smooth; canal short, recurved. 



Dimensions. — Long. 14.5 mm.; lat. 6.5 mm.; body-whorl 10 mm.; aperture, including 

 canal, 7.5 mm.; canal i mm.; defl. 42 degrees. 



