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



found in Bell and Bexar counties, and near Fort Worth ; also at Pres 

 ton, Grayson county, on the Red river and at Austin. It is also 

 found near Fort Washita, Indian Territory. 

 Collection. — U. S. National Museum. 



SPATAN^GIDJE. 



Test bilaterally symmetrical, generally cordiform. Ambulacra un- 

 equal and petaloidal. A^iical disk compact. Mouth opening transversely 

 bilabiate or jientagonal, situated anteriorly. Anal oi)ening posteriorly 

 situated and sui^ra-matginal. Spines of different" sizes. 



ENALLASTER D'Orbigny. 



Enallaster texanus (Roemer). 



Plate XXXIX, Figs. 2a-g. 



Toxaster texanus Roemer, 1849. Texas, etc., p. 393. 



Toxaster texanus Roemer, 1852. Die Kreidebildungeu von Texas, p. 85, PI. 10, Fig. 3. 

 Toxaster ungula Giebel, 1853. Jaliresber. des naturw. Vereiii.s in Halle, p. 373. 

 Enallaster texasus d'Orbigny, 1853-60. Paldont. frauf-aise, vol. 6, p. 184, PI. 850, 



Fig. 1-7. 

 Toxaster texanus Conrad, 1857. U. S. and Mex. Bound. Siirv. Rept., vol. 1, pt. 2, p. 145, 



PI. 1, Fig. 2a-2c. 

 Enallaster texanus Desor, 1858. Synop. des fichinides fossiles, p. 358. 

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

 Toxaster texanus Meek, 1864. Smith. Misc. Coll., vol. 7 (177), p. 3. 

 Enallaster texanus Clark, 1891. Johns Hopkins University Circulars, No. 87, p. 77. 



Determinative characters. — Test oblong, cordiform, broad in anterior 

 portion, contracted and truncated posteriorly, with deep anterior 

 groove; upper surface convex, elevated; base flat, depressed at the 

 mouth Oldening ; sides rounded ; apex excentric and posterior. Ambu- 

 lacra narrow and unequal, the posterolateral pair much shorter than the 

 others. Apical disk small and comj)act. Anal opening situated high 

 above the margin. 



Dimensions. — Length, 1| inches; width, 1^ inches; height, § inch. 



Description. — The exact limitations of this species have in most of 

 the earlier publications been very imperfectly designated. Other 

 forms, even one of a different genus, have been included. The test 

 is oblong, cordiform, and elevated. The upper surface is convex, with 

 a well-defined anterior groove, narrow and slightly depressed at its 

 head. On the posterior face the surface is truncated to the margin. 

 The sides are rounded and inflated. The base is flat, except for the 

 peristomial depression near the anterior margin and the central ele- 

 vated region extending from the same to the posterior border. 



The ambulacral areas are narrow and very unequal. The antero- 

 lateral pair are large and curved backwards in their upper i)ortions. 

 The pores are very unequal ; tbose of the anterior zone are small and 

 near together, those of the posterior elongated, the external nearly^ 



