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University of Calif omi-a Publications in Geology [Vol. 12 



to cordiform ; posterior portion slightly truncated. Test greatly de- 

 pressed ; upper surface rising gently from the ambitus to the summit, 

 which is immediately behind the apical system on the small odd pos- 

 terior interambulaeral ridge. Petals symmetrical ; those of the bivium 

 slightly more than seven-tenths the length of the anterior lateral petals. 

 Poriferous area broad, each being as wide as the interporiferous area. 

 Inner rows of pores in the lateral petals extend in approximately 

 parallel lines to the end, whereas the outer rows diverge and then con- 

 verge again close to the inner rows ; odd anterior petal slightly nar- 

 rower than the lateral petals of the trivium and the rows of pores 

 diverge slightly to their extremities. All the petals situated in 

 rather deep sulci, that of the odd anterior one continuing through a 

 broad, well defuaed notch in the ambitus to the peristome on the lower 

 surface. Apical system small and posterior to the center of the test. 

 Under side nearly flat, with a slight tendency to be convex. Peris- 

 tome transversely suboval and somewhat sunken, with a distinct pos- 

 terior labrum. Periproct placed high up on the posterior truncation 

 of the test. The test covered by irregidarly spaced, perforate, pri- 

 mary tubercles interspaced with numerous milliaries. 



Related forms. — Hcmiaster calif ornicus closely resembles the north- 

 ern California species, Epiastcr elepressus Kew, but differs in the less 

 strongly depressed test, and in that the petals of the bivium are of 

 greater length. 



Geologic horizon. — Chico formation. Upper Cretaceous. 



Localities. — Holotype from Redding, Shasta County, California ; 

 figured specimen from Santa Ana Mountains, Orange County, Cali- 

 fornia, Univ. Calif, loc. 2139. 



HEMIASTEE CHOLAMENSTS Kew, n. sp. 

 Plate 41, figures la, 16, Ic, Id 



Cotypes.—Nos. 11338 and 11343 Univ. Calif. Coll. Invert. Pal. 



Test small. Measurements of holotype : anteroposterior diameter 

 25.3 mm., transverse diameter 27 mm., greatest height 20.7 mm. Am- 

 bital outline subcircular to subpentagonal ; posterior end slightly trun- 

 cated. Sides of test nearly vertical, with the upper surface low, reg- 

 ularly rounded, and declining toward the anterior portion of the test. 

 A small, sharp ridge is present in the posterior interambulaeral area, 

 which extends from the apical system to the periproct. Summit 

 slightly posterior to the apical system. Apical system very small, and 



