206 CALIFORNIA ACADEMY OF SCIENCES. 



the outline of the lip and posterior sinus, form in .the middle of the whorl an angle open anteriorly; 

 transverse ornamentation more prominent on apical whorls; suture impressed, distinct; aperture 

 elliptical; outer lip thin, arcuate anteriorly; posterior sinus shallow, wide; anterior sinus short; 

 columella slightly curved to left; spirally ridged. 



DimensioJis. — Long. 26.5 mm.; lat. 9 mm.; body-whorl 14.5 mm.; aperture including 

 canal, 11 mm.; defl. 22 degrees. 



Distinguishable by the beautiful wavy incremental lines, which are quite 

 prominent in most specimens. Some of the shells reach a length of 40 mm. Grades 

 imjJerceptibly into D. inerrah. 



Not uncommon in the lower San Pedro series at Deadman Island and San 

 Pedro, and in the upper San Pedro series at Deadman Island, San Pedro, Los 

 Cerritos, Long Beach, and Crawfish George's. Found in the Pleistocene at Spanish 

 Bight and Pacific Beach, San Diego; and at the old irrigating ditch and Barlow's 

 ranch, Ventura. 



Living. — San Pedro, south; Cerros Island; Lower California (Cooper). 



Pleistocene. — San Pedro to San Diego (Cooper): San Pedro (Arnold). 



175. Drillia johnsoni, sp. nov. 



Plate VIII, Fio. 17. 



Shell of medium size, turreted; whorls eight or nine, nearly flat, each crossed by about 

 thirteen prominent, rounded, equal, equidistant, oblique ribs, which begin at anterior portion of whorl 

 and extend for about two-thirds distance across whorl, where they become nearly obsolete; a sutural 

 band occupies the upper third of the whorl; lower portion of whorl with five deep, channel-like 

 sulcations; sutural band with strong, oblique incremental lines; suture appressed, undulating; 

 aperture subelliptical; outer lip arcuate; posterior sinus narrow, rather deep; anterior sinus short, 

 recurved; columella incrusted; body-whorl convex, extended below, with revolving sulcations on 

 lower portion; transverse ridges obsolete on lower portion. 



Dimensions — Alt. 32 mm.; lat. 11 mm.; body-whorl 16.8 mm.; aperture, including canal, 

 12 mm.; canal 2 mm.; defl. 25 degrees. 



Resembles P. montereyensis, but is distinguishable by larger size, less promi- 

 nent but more sculptured sutural band, longer and more oblique ribs, and more 

 numerous spiral sulcations. Distinguishable from P. aurantia by much larger size, 

 more prominent and more sculptured sutural band, more distinct spiral sulcations, 

 longer and less oblique aperture, and a recurved rather than a straight anterior 

 sinus. Pronounced a new species by Dr. Dall. Named in honor of Henry R. 

 Johnson of Washington, D. C, who has prepared many of the drawings used in 

 illustrating this paper. 



Type specimen from upper San Pedro series of San Pedro. The specimen 

 figured is the tyjie, which is now in the United States National Museum. Found 

 also in the upper San Pedro series at Deadman Island by W. B. Harber. 



Pleistocene. — San Pedro (Arnold; Barber). 



