142 University of California Publications in Geology [Vol. 12 



tively wider ; and in that in all the petals the rows of pores are more or 

 less curved, whereas in those of the bivium they extend in parallel lines 

 to the end. It may be compared to Cassididus {Rhynch opygus) lyelli 

 (Conrad), but differs in having a test which rises almost directly 

 from the ambitus, whereas in the latter form the marginal area is 

 thickened and has a rather flattened abaetinal surface. 



Geologic horizon. — Vaqueros formation. Lower Miocene; associated 

 with Cassididus {Rhynchopygus) ellipticus Kew and Terehratalia 

 henncdyi ( ?) Dall. 



Locality. — Holotype from Santa Ynez River, east side of Oso Creek, 

 Santa Barbara County, California, Univ. Calif, loc. 3132. 



Genus CATOPYGUS Agassiz 



CATOPYGUS (?) CALIFORNICUS Kew, n. sp. 

 Plate 40, figures 2a, 2b, 2c, 2d 



Holotype. — No. 11014 (internal cast) Univ. Calif. Coll. Invert. Pal. 



A cassidulid of small size. Measurements of specimen no. 11014: 

 anteroposterior diameter 18.3 mm., transverse diameter 17 mm., great- 

 est thickness 14 mm. Test globular in shape ; outline from above 

 subquadrate. Broadest anterior to the center of the test ; somewhat 

 truncated behind in the posterior odd interambulacral area. Upper 

 surface greatly elevated to the summit, which coincides with the apical 

 system. An interambulacral keel, faintly developed near the apical 

 system, extends to the perii^roct, where it is quite prominent. Apical 

 system subeentral. Ambulacra narrow and subpetaloid ; two rela- 

 tively large pores in each plate ; pores in iimer row circular, whereas 

 those of outer row are oval ; interporif erous area about the width of 

 each poriferous area. Inferior surface slightly convex and somewhat 

 keeled on posterior part. Peristome comparatively large, sunken, and 

 with a posterior labruni ; situated close to the anterior margin of the 

 test. Periproct relatively large, round in outline, and placed high up 

 on the posterior truncation of the test. 



Geologic horizon. — Chico formation, Upper Cretaceous. 



Locality. — Holotype from Contra Costa Hills, Alameda County, 

 California. 



