Weno and Pawpaw Formations 109 



EPIASTER AGUILERAE Bose 

 PI. 5, fig. 5; PI. 8, fig. 7 



1910: Epiaster aguilerae Bose, Inst. Geol. Mex., Bol. 25, p. 173, pi. 47, figs 2-4, 6-7; 



pi. 48, figs. 1, 2, 4. 

 1920: Epiaster aguilerae Winton and Adkins, Univ. Texas Bull. 1931, p. 68. 



MEASUREMENTS : Bose's 



type I II 



mm. mm. mm. 



Length _ 77.2 66.2 48.0 



Width 69.1 65.5 43.5 



Height . 39.0 32.0 24.0 



Apical system to posterior margin 43.9 37.0 29.0 



Two individuals from the basal Fort Worth limestone near Fort Worth 

 are referred to this species, which was described from Subdivision 5 (Fort 

 Worth formation) of Cerro de Muleros on the basis of one imperfectly 

 preserved individual. The individual figured in this paper is of the same 

 proportions as Bose's individual but about one-seventh smaller. It differs 

 also in having the antero-lateral ambulacra diverge at a greater angle, 

 and in being slightly taller and longer from the apical system back : but 

 the last two features mentioned are due in part to a small amount of end- 

 wise crushing suffered by this fossil. In other respects it agrees with 

 Bose's description. This echinoid is proportionately broader and shorter 

 than the typical Fort Worth limestone, Hemiaster elegans Shumard, of the 

 form figured by Adkins and Winton 1 and has a decidedly rounded, non- 

 angular contour as compared with that species. It will be noted also that 

 the ambulacra are narrower, more flexuous (near the ambitus), and sunk 

 in much shallower grooves-than in H. elegans. The madreporite is smaller 

 than in H. elegans- or in Macraster texanus Roemer. 3 No fascioles are 

 visible. In longitudinal section H. elegans is much taller, straight-sided 

 and less evenly rounded posteriorly than E. aguilerae, and its inter-ambul- 

 acral areas, including the median posterior keel more elevated. In the 

 individual at hand the periproct is situated lower than in material of 

 H. elegans collected in the Fort Worth limestone at Fort Worth, but higher 

 than in examples figured by Clark, 4 and the anterior notch is deeper than 

 in Clark's figures but shallower than in some material collected by me. 



'Univ. Texas Bull. 1945, pi. 8, fig. 3. 



"Compare Clark, in Clark and Twitchell: U. S. G. S. Mon. LIV, pi. XL1II. 



3 B6se: Inst. Geol. Mex. Bol. 25, pi. XLVIII, figs. 1-3, 5. 



'Clark, ibid., pi. XLII, fig. 1-4. 



