2!K) CAIJKOUNIA ACAMKMV <ll' SlIKNl'KS. 



Family I.Wll. TK I Im )K 1 D/E. 

 Gciuis Triforis I>ishai/cs. 



Sliell sinistral, scul|)liiici.i, jjiaiuilar; wluirls i)uim.Tous, tuniiiiialinj^ bcluvv in a small apcr- 

 turf, with tubular anterior canal; opposite this canal is sometimes a second one upon a varix, 

 marking the position of a former aperture. 



Triforh percersus T.inii. is a cliuriU-U'iislic sprcies. 



313. Triforis adversa Moattujn. 



Triforis adversa Mont., Test. Brit., p. 271, 1803. Cpk., Brit. Assn. Rept., 1863, p. 660. Tryon, 

 Man. Conch., Vol. IX, p. 187, PI. XXXIX, fig. 51, 1887. Keep, West Coast Shells, 



p. 47, 1 89 2. 



Shell sinistral, with cancellated sculpture, caused by three spiral and numerous ecjually as 

 prominent transverse ridges; resembles Bittium rui^aliim somewhat in sculpture. 



One imperfect specimen from lower San Pedro series at Deadman Island 

 collected by Mrs. Oldroyd. 



Living. — Vancouver to Santa Barbara Island (( arpenter). 



Pleistocene. — San Pedro (Oldroyd). 



Supcrfaniily LERITI 1 1 ACEA. 

 Kaiuily I>X\'11I. CKKITUKJl'SlD.E. 



Gemis Seila A. Adums. 



-Shell spiral, elongated, many whorled, frequently varicose; aperture channeled in fmni, 

 with a less distinct canal posteriorly; outer lip not reflected; nuclear whorls sinistral; trans- 

 versely lirate. 



314. Seila assimilata C. B. Adams. 



Plate IV. Fig. 8. 



Ccrithiopsis assimilata C. B. Au., Maz. Cat., No. 563, 1852. Cpr., Brit. Assn. Rept., 1863, p. 660. 

 Trvon, Man. Conch., Vol. IX, p. 174, PI. XXXVI, fig. 59, 1887. Cooper, 7th Ann. 

 Rept. Cal. St. Min., 1888, p. 232. Keep, West Coast Shells, p. 48, 1892. 



Shell small, thin, turreted; nuclear whorls sinistral; whorls ten, ornamented with three 

 prominent, sharp, equal, equidistant, raised spiral lines; interspaces between ridges crossed by 

 numerous fine lirulae; suture indistinct, not distinguishable on ujiper portion of spire; base truncated 

 abruptly, flat; aperture subquadrate; outer lip thin, not efl'use; inner lip simple; columella recurved; 

 canal short. 



Dimensions. — Long. 10 mm.; lat. 3.8 mm.; body-whorl 3.8 mm.; aperture 2.1 mm.; defl. 

 24 degrees. 



Resenil)Ie8 the Bltlinina, but is distin,2;nisliable by the strong spiral lines. 

 Specimen identified by Dr. Dall. Rare in lower San Pedro series at San Pedro. 



