80 MESOZOIC ECHINODERMATA OF THE UNITED STATES. [bull. 97. 



tubercles and intervening microscopic granulation. Apical disk com- 

 pact. Mouth opening transversely subpentagonal. Anal opening situ- 

 ated on truncated i^osterior margin. 



Description. — This species has a broad cordiform test, that is flattened 

 and slanting on the anterior upper surface, whence the name ohliquatvs. 

 The anterior groove is deep, wider at its head, and cuts broadly into 

 the anterior margin. The posterior portion of the test is elevated near 

 the apex and obliquely truncated toward the margin. The sides are 

 sloping anteriorly, fuller i^osteriorly. The base is flat with a deep 

 peristomial dejiression. 



The ambulacral areas are narrow and unequal. The anterolateral 

 pair are slightly depressed and curved backwards in the upper portion. 

 The pores are unequal, those of the anterior zone small and near 

 together, those of the posterior elongated, the exterior much more so 

 than the anterior series (PI. xl, Fig. 1/). There are about forty pairs 

 of pores in each zone. 



The posterolateral pair are short and slightly depressed. The 

 pores are more nearly equal and about twenty-four pairs are found in 

 each zone. The single ambulacrum is i^laced in the anterior groove 

 and is much wider than the paired ambulacra. The pores of the 

 different i)lates vary in size and position (PI. XL, Fig. le). The plates ; 

 in the lower portions of the areas are large and oblong in form. 



The surface of the test is covered with minute tubercles between 

 which is a microscopic granulation. The apical disk is small and com- 

 pact (PI. XL, Fig. li). 



The mouth opening is transversely subpentagonal (PI. xl, Fig. l/<). 

 The anal opening is oval and situated high on.the truncated posterior 

 margin (PL XL, Fig, Id). 



Belated forms. — Enallaster ohliquatus is separated from JE. texanus, 

 the only other representative of this genus from the Cretaceous deposits 

 of the United States, by its broader more depressed form, more sunken 

 anterior sulcus, and the lower position of the anal opening. It is closely 

 related to U. mexicanus, described by Cotteau, in 1890, from material 

 obtained from Mexico. 



Locality and geological horizon. — This species is from the Fredericks- 

 burg formation of the Comanche series (lower Cretaceous) of Texas. 

 It is characteristic of the alternating or Glen Eose beds of Austin and 

 Glen Rose. 



Collections. — U. S. National Museum; Texas Geological Survey. 



EPIASTEE D'Orbigny. 



Epiaster elegans (Shumard). 



Plate XLi, Figs, la-6; Plate xlii, Figs. la-&; Plate xliii, Figs. la-e. 



Hemiaster elegana Shumard, 1853. Kept. Expl. Red River of Louisiana in 1852, p. 210, 



PL 2, Figs. 4a-4c. 

 Toxaster elegam Gabb, 1859. Cat. Invert. Fossils Cretaceous, p. 19. 



