198 CALIFORNIA ACADEMY OF SCIENCES. 



Living. — Lower California (Carpenter): AVest Coast (Keep): Halfmoon Bay 

 (Arnold). 



Pleistocene. — San Pedro (Arnold): San Nicolas Island (Bowers. 



Superorder STREPTONEURA. 



Order CTENOBRANCHIATA. 



Superfamily TOXOGLOSSA. 



Family L. TEREBRID^E. 



Genus Terebra Bruguiere. 



Shell elongated, turriculated, narrow, solid; whorls numerous, rather flattened, with super- 

 ficially impressed sutures; aperture small, ovate, profoundh- notched at base; columella oblique. 



Terehra nehulosa Sowerby is a characteristic species. 



Section Acus (Humphrey) Gray. 



i6i. Terebra (Acus) simplex Carpenter. 



Myurella simplex Cpr., Brit. Assn. Rept., 1863, p. 657; Ann. & Mag. Nat. Hist., 3rd Sen, 

 Vol. XV, 1865, p. 395. Gabb, Pal. Cal., Vol. TI, p. 78, 1869. Cooper, 7th Ann. 

 Rept. Cal. St. Min., 1888, p. 253. Keep, West Coast Shells, p. 56, fig, 40, 1892. 



Terebra simplex Cpr., ^7! variegaia Gray (^fide Tryon, Man. Conch., Vol. VII, p. 14, 1885). 



Terebra (Acus) simplex Cpr., Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 207. 



vShell small, turreted, slender; ape.x acute; whorls ten to eleven, flat; sculpture consists of 

 about fourteen faint, transverse ribs, each terminated on anterior end by a prominent node: a pseudo 

 suture separates the row of nodes from the main part of the whorl; incremental lines visible; suture 

 impressed, distinct; aperture subelliptical; outer lip thin, slightly arcuate anteriorly: inner lip smooth; 

 plication on columella; sinus short. 



Ditnensions. — Long. 33 mm.; lat. 9 mm.; body-whorl 13 mm.; aperture 9 mm.; defl. 

 18 degrees. 



Sculpture in this species is quite variable; some specimens have the I'ow of 

 nodes prominently elevated, others show only a little constriction at upper third of 

 transverse ridge. 



Common in upper, rare in lower San Pedro series of the San Pedro region. 

 Rare in the Pliocene of Deadman Island and Timra's Point. Found in the Pleis- 

 tocene at Barlow's ranch, Ventura, and at Twenty-sixth Street, Spanish Bight, and 

 Pacific Beach, San Diego. 



Jjiving. — Santa Barbara to San Diego (Cooper). 



Pleistocene. — Santa Barbara to San Diego (Cooper): San Pedro; San Diego; 

 Ventura (Arnold). 



Pliocene. — San Diego well (Dall): San Pedro (Arnold). 



