144 MISSISSIPPIAN BRACHIOPODA 



STEOPHALOSIA SCINTILLA Beecher 

 Plate XVIII, Figs. 19-23 



1890. Strophalosia scintilla Beecher, Am. Jour. Sci. (3), vol. 40, p. 243, 



pi. 9, figs. 10-13. 

 1892. Strophalosia scintilla Hall and Clarke, Pal. N. Y., vol. 8, pt. 1, 



pi. 15B, figs. 32-34. 

 1908. Strophalosia scintilla Rowley, Mo. Bureau Geol. and Mines, vol. 8, 



2nd ser., p. 76, pi. 17, figs. 26-29. 



Description. Shell very small, attached to foreign objects by nearly the 

 entire surface of the pedicle valve, wider than long,transversely subellip- 

 tical in outline with the posterior margin truncated, the hinge-line a little 

 shorter than the greatest width. The dimensions of a nearly complete 

 example are : length 1.9 mm., width 3.1 mm. 



Pedicle valve adherent to foreign objects, usually to shells of other 

 brachiopods, its margin elevated and usually furnished with a variable 

 number of slender, procumbent spines, rarely more than six or seven in 

 number and sometimes wholly wanting, the spines rarely or never occur 

 along the cardinal margin ; cardinal area low and broadly triangular, with 

 a small delthyrium closed by a deltidium, the hinge-teeth small, but well 

 developed, unsupported by dental lamellae'. 



Brachial valve convex at the beak, becoming flat or concave anteriorly ; 

 the beak inconspicuous, scarcely or not at all extended beyond the hinge- 

 line ; the surface marked by concentric lines of growth. 



Internally the adductor muscular scars are small and the surface is 

 pustulose near the margin; the brachial impressions have not been 

 observed. 



Remarks. This species is the smallest member of the genus so far 

 known in the faunas under consideration. It resembles S. Jceokuk in the 

 almost complete attachment of the pedicle valve to foreign objects, but it 

 differs from that species, in addition to its smaller size, in the smaller 

 number and less crowded attaching spines, and in the apparent absence 

 of these spines along the cardinal margin. This last character seems to 

 be a good one for the species, in no case have the spines been observed 

 growing from the central portion of the cardinal margin, and in only one 

 or two examples have they seemed to be present at one of the outer ex- 

 tremities of this margin, even these not being so well preserved as to make 

 it certain that they are spines. 



Horizon. Louisiana limestone of the Kinderhook. 



