ARNOLD — THE PALEONTOLOGY AND STRATIORAPHV OF SAN PEDRO. 323 



368. Leptothyra bacula Carpenter. 



Leptonyx bacula Cpr., Brit. Assn. Rcpt., 1863, p. 652. Keep, We^t Coast Shells, p. 87, 1892. 

 Leptothyra bacula CpR., Gabb, Pal. Cal, Vol. II, p. 85, 1869. Cooper, 7th Ann. Rept. Cal. St. 

 Min., 1888, p. 245. Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892. p. 199 



Shell small, turreted, thick; surface sculptured by fine spiral lines; no umbilicus; aperture 

 circular, slightly angulated anteriorly. 



Dimensions. — Alt. 2 mm.; lat. 2.5 mm. 



The specimen from the Pleistocene shows the original pink color of the living 

 shell, and looks very much like a very small Horrisia norrisii, except that the Lep- 

 tothyra has no umhilicus. 



Distinguishable from L. carpenferi and L. paucicostata by its much finer spiral 

 sculpture and pinkish color. 



One specimen from the lower San Pedro series of Deadman Island; also 

 found in the lower San Pedro series at Los Cerritos. Found in the Pleistocene at 

 bath-house, Santa Barbara. 



Living. — Monterey to Catalina Island (Cooper). 



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

 bara (Arnold). 



369. Leptothyra carpenteri Pilsbry. 



Leptothyra carpenteri Pilsbry, Tryon, Man. Conch., Vol. X, p. 247, PI. XXXIX a, figs. 26-29, 

 18SS; Nautilus, July, 1890. Williamson, Proc. U, S. Nat. Mus., Vol. XV, 1892, p. 199. 



Leptothyra sanguineus Linn., Cpr., Brit. Assn. Rept., 1863, p. 652. 



Leptothyra sangiiinea Cpr., Gabb, Pal. Cal., Vol. II, p. 85. 1869. Tryon, Syst. Conch., Vol. I, 

 PI. II, p. 312, 1882. Cooper, 7th Ann. Rept. Cal. St. Min., p. 245, 188S. (Not 

 Leptothyra sanguineus LiNN., Syst. Nat., 1760.) 



Lrptonyx sangui)iea LiNN. , Keep, West Coast Shells, p. 87, fig. 73, 1892. 



Shell small, subconical, thick; spire only slightly elevated; whorls three to four, slightly 

 convex; body-whorl subangulate anteriorly; whorls ornamented by nine to ten fine, spiral ridges; 

 aperture circular; not umbilicated; tubercle on lower portion of outer lip; suture slightly im- 

 pressed, distinct. 



Dimensions. — Alt. 8 mm.; lat. lomm. ; defl. 100 degrees. 



Distinguishable from L. paucicostata by larger size, greater number and less 

 prominence of spiral ridges, and by less prominence of suture; distinguishable from 

 L. bacula by less number and greater j^i'ominence of sjiiral ridges. 



Found in lower San Pedro series at Deadman Island, and San Pedro; and 

 in the ujij^er San Pedro series at San Pedro and Crawfish George's. 



Living. — Straits of Fuca to San Diego; Japan (Cooper). 



Pleistocene. — Santa Barbara (Cooper): San Pedro (Arnold). 



370. Leptothyra paucicostata Dull. 



Leptothyra paucicostata Dall, Am. Jour. Conch., Vol. VII, 1872, p. 131, PL XV, fig. 10. Tryon, 

 Man. Conch., Vol. X, p. 248, PI. LXIII, fig. 27, 18S8. Cooper, 7th Ann. Rept. Cal. 

 St. Min., 1888, p. 245. 



