138 University of California Publicaiions in Geology [Vol. 12 



end of the petals. Inferior surface flat. Ambulaeral furrows well 

 marked; divide close to the peristome with the exception of the odd 

 anterior one, which bifurcates when about one-fourth the distance 

 from the peristome to the margin ; short branches are sent out toward 

 the lunules and longer ones are given off close to the margin. Peris- 

 tome round and situated anterior to the center of the test. Periproct 

 situated about twice its own diameter posterior to the peristome, but 

 still slightly anterior to the center of the test. Tubercles on the upper 

 surface very small, scrobicular, and crowded; those of the under side 

 larger and irregularly spaced, being absent between the main branches 

 of the ambulaeral furrows but present in the median furrow. 



Geologic horizon. — Upper San Pedro formation. Pleistocene. 



Locality. — Newport Beach, Orange County, California. 



Suborder SPATANGINA Jackson 

 Tribe CASSIDULOIDEA Duncan 



Family CASSIDULIDAE Agassiz 

 Genus CASSIDULUS Lamarck 



Subgenus RHYNCHOPYGUS d'Orbigny 

 CASSIDULUS (EHYNCHOPYGUS) CALIFORNICUS (F. M. Anderson) 

 Plate 39, figures la, Ih, Ic, Id 



Cassidulus californicus F. M. Anderson. Proc. Acad. Sci., ser. 3, Geol., 



vol. 2, 1905, p. 194, pi. 13, figs. 6-7. 

 Cassidulus californicus. Arnold, U. S. Geol. Surv. Bull., no. 396, 1909, 



pp. 13, 112, pi. 4, figs. 1, la. 

 Cassidulus californicus. Arnold and R. Anderson, ibid., Bull., no. 398, 1910, 



pp. 70, 284, pi. 26, figs. 1, la. 

 Cassidulus californicus. Stefanini, Boll. Soc. geol. ital., vol. 30, 1911, 



p. 696. 



Cassidulus californicus. Clark and Twitcliell, U. S. Geol. Surv. Men., vol. 

 54, 1915, p. 140, pi. 65, figs. 2a-2b. 



Holotypc. — Calif. Acad. Sci. Coll. (destroyed in San Francisco 

 fire) ; neofype, specimen no. 11348 Univ. Calif. Coll. Invert. Pal. 



Test small. Measurements of specimen no. 11348 : anteroposterior 

 diameter 18.2 mm., transverse diameter 14.5 mm., greatest height 8.2 

 mm. Ambital outline subelliptical ; slightly broader behind than in 

 front. Upi^er surface regularly rounded from a thickened margin to 



