52 PROCEEDINGS OF THE CALIFOKNIA 



Mr. Gabb presented the following paper by Mr. Rdmond : 



Description of Four New Species of Echinodermata, from 

 the Tertiaries of Contra Costa County. 



BY AUGUSTE KEMOND. 



Astrodapsis Conrad. 

 A. Whitneyi Remond. 



Disk circular, or sub-pentagonal, slightly notched at the extremity of the 

 ambulacra. 



Apex central and elevated ; edge depressed. 



Ambulacra! star symmetrical, prominent near the apex ; petals equal, reach- 

 ing to the margin of the disk. 



Interambulacral spaces much depressed near the edge. 



Lower surface slightly and gradually concave ; furrows well marked and 

 straight. 



Mouth central, circular ; anal aperture small, sub-marginal. 



Papillary tubercles somewhat remote, smaller above than beneath, situated in 

 wide and shallow cells ; miliary tubercles very numerous and crowded, both on 

 the superior and inferior surfaces. 



Greatest diameter 1.8 inches 



Smallest diameter 1.65 " 



Height 0.3 " 



Locality : Kirker's Pass formations. Found in lower pliocene beds. 



The genus astrodapsis, to which I have referred the above species, was indi- 

 cated by Mr. Conrad, in the Pacific Railroad Reports, Vol. VII, Pala?onto- 

 logical Report, page 196, without any generic description. 



The genus is closely allied to clypeaster, but differs from it in having the 

 petals of the ambulacral star extending to the edge of the disk, opened at the 

 extremity, and in the margin of the disk being slightly notched at the extremity 

 of each petal. The inter-ambulacral spaces are depressed. On the under surface 

 there is a deep groove corresponding to each petal. 



My collection, and that of the State Geological Survey. 



A. tumid-us Remond. 



Disk rounded sub-pentagonal, tbick, rounded on the edge, very slightly 

 notched at the end of the ambulacral areas. 



Apex small, central, depressed. 



Ambulacral petals symmetrical, very prominent, reaching to the margin, 

 longitudinally grooved by a median line. The outer pores of the petals 

 abruptly depressed on each side. 



Inferior surface slightly concave. 



Mouth central, small, rounded. 



Ambulacral furrows straight, well marked. 



Anus small, sub-marginal. 



