ACADEMY OF NATURAL SCIENCES. 53 



Papillary tubercles numerous, especially in the ambulacral areas, and in the, 

 center beneath, not prominent, situated in comparatively deep and sub-angular 

 cavities. 



Greatest diameter 1.34 inches. 



Shortest diameter 1.26 " 



Height 0.34 " 



Locality : Kirker's Pass formations ; occurs as the preceding species ; also 

 two miles west of Walnut Creek House. 



From the collections of the California Academy of Natural Sciences, of the 

 State Geological Survey, and my own. 



Echinarachntus van Phels. 

 E. Brewerianus Rem. 



Disk small, oval-elongated, broader behind, rather thin. 



Upper surface slightly convex ; margin rounded. 



Apex posteriorly sub-central. 



Petals close, nearly symmetrical, the anterior and posterior ones the longest, 

 as wide as or even wider than the inter-ambulacral spaces ; ambulacral areas 

 composed of very narrow plates, widening on the margin. 



Inferior surface plane. 



Ambulacral furrows not visible in the specimens examined. 



Mouth small, central. 



Anus very small, sub-marginal. 



Papillary tubercles numerous, rounded, somewhat prominent, more crowded 

 beneath than above. 



Length 1.22 inches 



Width 1.06 " 



Height 0.30 " 



Locality : Two miles east of "Walnut Creek House ; from miocene beds. 



Collection of the State Geological Survey, and mine. 



This species is dedicated to Prof. W. H. Brewer, Botanist to the Survey. 



Clypeaster Lamark. 

 C. Gabbii Bern. 



Disk rather small, comparatively thick, varying from circular to sub-penta- 

 gonal and irregular sub-oval. 



Apex nearly central, sub-elevated ; margin rounded ; genital apparatus sub- 

 angular. 



Ambulacral star almost symmetrical ; petals about equal in length, elongated, 

 open at their extremities. 



Inferior surface flat near the edge, and gently concave in the center. 



Mouth depressed, sub-central. 



Ambulacral furrows straight, slightly marked. 



Anal aperture very small, marginal. 



