1920] Keiv: Cretaceous and Cenozoic Echinoidea 



65 



closer to the inner row, and, as the distal portion is approached, both 

 rows strongly diverge. Outer rows of pores slightly sunken in all 

 petals. Inferior surface flat, with very faint, straight, undivided 

 ambulaeral lines in indistinct broad grooves, which do not reach the 

 margin. Peristome subpentagonal in outline and slightly anteriorly 

 eccentric. Periproct round, supramarginal, and placed about its own 

 diameter from the edge of the test. Tubercles on the superior surface 

 very small and crowded ; those of the inferior surface larger and 

 placed in well defined scrobicules. 



Related forms. — This species closely resembles Scutella gabbi 

 (Remond), but it may be separated from the latter by the position of 

 the periproct, which is situated fartlier from the edge of the test than 

 in S. gabbi, in which it is nearly marginal; the test is less elevated 

 and slopes posteriorly to a thinner margin ; the marginal outline is 

 more subovate ; and the petals are narrower and more strongly 

 elliptical in outline. The anteroposterior profile of the test resembles 

 S. andersoni Twitchell, but 8. blancoensis may be distinguislied by 

 its lack of distinct posterior marginal notches, and from the fact that 

 the periproct is supramarginal and not marginal. From Scutella 

 merriami (Anderson) it differs in being less tumid, in having a sub- 

 ovate marginal outline, and in the strongly supramarginal position 

 of the periproct. 



Oeologic horizon. — San Lorenzo series, Oligocene. 



Localities. — Basal sandstone, sea cliffs north of lighthouse, Cape 

 Blanco, Oregon, Leland Stanford Jr. Univ. Dept. Geol. loc, N. P. 

 26, and Calif. Acad. Sci. loc. no. 17. 



SCUTELLA COOSENSIS Kew, n. sp. 

 Plate 8, figures la, Ih 



Holotype.—'No. 446 Calif. Acad. Sci. Coll. Pal. 



Test of medium size, and greatly depressed. Measurements of holo- 

 type : anteroposterior diameter 52 mm., transverse diameter approxi- 

 mately 80 mm., greatest height approximately 8 mm. Marginal out- 

 line transversely suboval. Margin thin, with the upper surface gently 

 and regularly arched to the summit, the latter being situated slightly 

 anterior to the center of the test. Apical system central ; madreporic 

 area large, four genital pores present opposite the four lateral corners. 

 Ambulacra extremely wide at the ambitus, the odd anterior one being 

 four times the width of the adjoining interambulacra, the other am- 



