Vol. 5] Pack. — Tertiary Echinoids of California. 



277 



half of their length. Poriferous zones broad, together forming 

 over half the width of the petal. Anterior petal broad, wide 

 open at the end, inner rows of pores diverging gradually to the 

 end of the petal ; poriferous zones about the same width as in the 

 other petals, but enclosed area much broader. Ambulacral plates 

 enlarging and area widening rapidly from the ends of the lateral 

 and posterior petals, less rapidly from the anterior one. Two 

 or three pairs of pores in rapidly diverging rows are traceable 

 from the ends of the petals. Actinal surface flat, mouth opening 

 central and slightly sunken. Ambulacral furrows deep, traceable 

 to the margin. Near the margin these furrows show a slight 

 tendency to branch, but in the specimens examined they were too 

 poorly preserved to trace. 



Anal pore supramarginal, separated from the edge by a dis- 

 tance equal to its own diameter. Tubercles somewhat larger on 

 the actinal surface, especially near the mouth. 



Dimensions : Longitudinal diameter 65 mm. ; height 8 mm. 



Occurrence : In the Vaqueros formation in Torry and Sespe 

 canons, Ventura County. 



This species is closely allied to Scutella gabbi, from which it 

 differs in attaining a greater size, in having a slightly undulating, 

 marginal outline, in having deeper and better marked furrows on 

 the actinal surface, and in having the anal pore entirely on the 

 upper surface. From Scutella interlineata it differs in having a 

 central apical system. 



SCUTELLA (?) NOERISI, n. sp. 

 PI. 23, fig. 3. 



Test sub-circular in general outline, with deep, broad, margi- 

 nal notches in the edges of the ambulacral areas. The two pos- 

 terior notches are much deeper than are the anterior ones, and 

 truncate the posterior interambulacral space on either side of the 

 median line, shaping the posterior end of the test into a promi- 

 nent process. The test when viewed from above has a leaf-like 

 appearance. Test much depressed, edges markedly thin, abac- 

 tinal surface very slightly arched, apex central ; actinal surface 

 flat or gently concave. Mouth central, slightly sunken; ambu- 

 lacral furrows poorly shown in the specimens examined, but evi- 



