48 



University of California Publications in Geology [Vol. 8 



immediately surrounding the lunule somewhat tumid. Ambulacral 

 notches broad, deep, contracting slightly near the margin of the test 

 and tending to close. Both interambulacral lunule and ambulacral 

 notches varying somewhat in size. Apical system central. Petals 

 nearly closed, and reaching about two-thirds the distance to the mar- 

 gin. Petals rather narrow. The two lateral petals of the trivium 

 broader and averaging nine per cent shorter than the others. Inter- 

 poriferous areas slightly lenticular, and at widest part about same 

 dimensions as the poriferous area. Actinal side flat, and marked by 

 deep ambulacral furrows which branch immediately from the peristome 

 and a second time a short distance from the outer margin. The main 

 furrows are broad, shallow and straight, deepening as the ambulacral 

 notches are approached. Mouth small and not sunken. Anus situated 

 on the inferior surface slightly anterior to the interambulacral lunule. 



This species closely resembles the Recent Encope calif omica Verrill, 

 from which it differs in the thicker margin and the commonly closed 

 ambulacral notches of the Recent species. 



Occurrence. — Lower Division of the Carrizo formation at Coyote 

 Mountain and Carrizo Valley. University of California Localities 739 

 and 2064. 



Measurements 



No. 10050 No. 10051 No. 10052 No. 10053 No. 10054 



Anteroposterior diameter .... 92.7 mm. 110.9 115. 110.6 84.4 



Transverse diameter 96.0 105.8 105. 110.0 85.8 



Greatest thickness 10.3 15.3 8.9 



CLYPEASTEE DESERTI, n. sp. 

 Plate 3 



Test large and pentagonal to subcircular in outline. Margins 

 broadly notched opposite the interambulacral areas, the two lateral 

 posterior notches being larger, and the median posterior notch smaller 

 than the anterior ones. Test not markedly thick, but margin swollen 

 excepting opposite the posterior interambulacral area. Apical system 

 central and raised. Petals short, very tumid, and reach about half the 

 distance to the edge of the test. Only petals of bivium closed. Anterior 

 petal longer than the other four, which are of approximately the same 

 length. Poriferous area large, and pores conjugate. Tubercles small 

 and of the same size on both sides. Actinal surface flat, with mouth 



