106 University of California Publications in Geology [Vol. 12 



which it is often found associated, but may be distinguished by its 

 distinctly pentagonal marginal outline ; relatively narrower petals ; 

 deeper interambulacral depressions on the upper surface ; more ele- 

 vated petals ; and a test broadly subcorneal in shape. From A. alius 

 Kew it differs in having interambulacral depressions, and from A. 

 antiselli Conrad in having a thinner margin and a pentagonal outline. 

 The ornamented plates which are developed on the slightly weathered 

 specimens usually serve to distinguish it. 



Geologic Jwrizon. — Upper San Pablo group (Santa Margarita for- 

 mation). Upper Miocene. Occurs with Astrodapsis whitneyi and A. 

 titmidus (small, thick form). 



Localities. — San Juan River district, Univ. Calif, loc. 2721 (co- 

 types), and Quailwater Canyon, San Luis Obispo County, California 

 (U. S. Geol. Surv. Coll.) ; Slack's Canyon, Monterey County, Califor- 

 nia (Stanford Univ. Coll.). 



ASTEOD APSIS (?) PABLOENSIS (Kew) 



Plate 14, figures 2a, 2b, 2c 



Sculella pahJoensis Kew. Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, 1915, 



p. 369, pi. 39, figs. 6a, 66. 

 SciiteUa pahloensis. B. L. Clark, ibid., pp. 400, 403, 417, 425 (listed). 



Holotypc.—m. 10063 Univ. Calif. Coll. Invert. Pal. 



Size medium. Average measurements : anteroposterior diameter 

 42.2 mm., transverse diameter 40.5 mm., greatest thickness 8 mm. 

 Test thin and greatly depressed. Outline of test subcircular ; trans- 

 verse diameter usually greater than the anteroposterior diameter; 

 posterior interambulacral area strongly lobed; ambitus notched in 

 the ambulacral areas, the degree of notching being greater in the two 

 posterior areas ; margin thinner behind. Upper surface rising grad- 

 ually to the summit, which is anterior to the apical system, the latter 

 being central. Interambulacra flat. Ambulacra petaloid ; petals 

 slightly elevated, wide open at their extremities, and extending about 

 three-f oui'ths the distance from the apical system to the margin. Pores 

 conjugate ; inner rows of rounded pores diverge gradually until about 

 one-third the distance to the ambitus, and then converge slightly to 

 the end of the petal ; outer rows of elongate pores diverge somewhat 

 more than the inner rows and continue in this manner for over one- 

 half the distance to the end of the petal, when they converge quite 

 close to the inner rows at the end ; double rows of small, round pores 

 diverge from the end of the petals to the ambitus. Poriferous areas 

 wide, being about one-fourth the width of the petal ; areas between 



