FOSSILS OF THE BURLIXGTON GROUP. 409 



the subradials, wider than long, pentagonal in form, and 

 rounded or convex on the outer side above. Second radials 

 short, transversely oblong, or about twice as wide as long, 

 and all rounded on the outer side. Third radials (in four 

 of the rays seen) somewhat longer than the second, pen- 

 tagonal in form, but with their lateral margins so short as 

 to appear nearly trigonal; supporting the arms on their 

 .superior sloping sides. Anal pieces unknown. 



Arms round, rather slender, and after their origin on the 

 third primary radials, bifurcating on the seventh, ninth or 

 eleventh pieces in the different arms seen, and beyond this, 

 one arm is observed to bifurcate on the nineteenth piece 

 above ; all composed of slightly wedge-formed pieces, a 

 little wider than long. 



Proboscis (so-called), as observed nearly flattened by 

 pressure, two-thirds as wide as the body, and about four- 

 fifths as long as the arms; not expanded at the summit; 

 composed of moderate sized hexagonal pieces indented 

 (and probably perforated) at the corners. Column sub- 

 pentagonal near the base, where it is composed of alter- 

 nately thicker and thinner pieces, with a small apparently 

 pentagonal canal. 



Hight of body to top of first radials, 0.20 inch; breadth, 

 about 0.40 inch; length of arms, about 2.10 inches. Length 

 of proboscis above first radials, 1.70 inches; thickness of 

 column at its connection with the base, 0.15 inch. 



f This species is related to such forms as 8. car hiatus and 8. dichotomus, 

 Hall; 8. rusticus. White, and 8. Wachsmuthi, M. and TV., but differs 

 from them all too clearly to render a comparison necessary. 



LiH'-ality and position Upper division of the Burlington group, at 

 Burlington, Iowa. Lower Carboniferous. Xo. 295 of Mr. WACHSMUTH'S 

 collection. 



5.1 



