EOCENE ECHINODEKMATA. 151 



Hemipatagus subrosteatus Clark, n. sp„ 

 Plate LXIX, figures 2a-b. 



Determinative characters. — Test medium size, subcordiform, only slightly higher posteriorly, 

 longer than wide, nearly flat below, with broad anterior sulcus. Ambulacra broad, somewhat 

 depressed, the poriferous avenues subpetaloidal, the anterior pair longer than the posterior. 

 Interambulacra with a number of large scattered tubercles in the paired areas with deep areolas, 

 crenulate and perforate. 



Dimensions. — Length 33 millimeters; width 29 millimeters; height 14 millimeters. 



Description. — The single specimen of this species is much damaged on the lower surface 

 and posterior end, neither the peristome nor periproct being preserved. The testis of medium 

 size, subcordiform, only slightly higher on the posterior part than on the forward part of the 

 upper surface. It is longer than wide, the widest portion being only slightly forward of the 

 middle of the test. A broad anterior sulcus extends from the apex over the ambitus. The 

 lower surface is nearly flat. 



The ambulacra are nearly flush, somewhat depressed, the poriferous avenues subpetaloidal, 

 the anterior pair longer than the posterior. The pores are oval and connected by prominent 

 furrows. 



The interambulacra are somewhat elevated with a number of large, scattered tubercles in 

 the paired areas. The tubercles have deep areolas, and are crenulate and perforate. 



Belated forms. — This species is similar to H. argutus but is narrower anteriorly, has a less 

 cordate form, and is lower posteriorly. 



Locality. — Wilmington, N. C. 



Geologic horizon. — Castle Hayne limestone, upper Eocene or Oligocene. 



Collection.— U. S. National Museum (164652). 



Genus SCHIZ ASTER Agassiz. 



Schizastee lecontei Merriam. 



Plate LXIX, figures 3a-b. 



Schizaster (?) sp. Merriam, 1897, Jour. Geology, vol. 5, p. 773. 



Schizaster lecontei Merriam, 1899, California Acad. Sci. Proc, 3d ser., Geology, vol. 1, pp. 164, 165, PL XX, figs. 1, la. 



Schizaster lecontei Stefanini, 1911, Soc. Geol. italiana Boll., vol. 30, p. 697. 



Determinative characters. — Test small, cordiform, elevated, with a sharp ridge from apical 

 system to posterior truncation. Apex posterior to center of test. Ambulacra broad, depressed, 

 petals of posterior pair less than half the length of anterior. Peripetalous fasciole distinct, 

 Apical system posterior to center. Peristome well forward. Periproct high on truncated 

 posterior surface. 



Dimensions. — Length 20 to 23 millimeters. 



Description. — The specimens of this species are preserved only as impressions or casts, 

 badly crushed. The test is small, cordiform, upper surface much elevated, with a sharp ridge 

 running from the apical system to the posterior truncated surface. A broad groove notches 

 the anterior margin. 



The ambulacra are broad, the poriferous zones depressed, petaloidal, the petals of the 

 posterior pair very short, less than half the length of the anterior, sometimes almost circular in 

 outline. Pores elongated, apparently yoked. 



The interambulacra broad. Tubercles larger on the lower surface. Peripetalous fasciole 

 quite distinct on one specimen. Traces of what appears to be the lateral fasciole have been 

 seen beneath the periproct. 



Apical system excentric, posterior r anterior to the summit. 



Peristome well forward, broad two-lipped. Periproct high up on the truncated posterior end. 



