NATURAL SCIENCES OF PHILADELPHIA. 145 



Arms rouml, rather slender, and after their origin on the third primary ra- 

 dials, 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 subpentagonal near the base, 

 where it is composed of alternately thicker and thinner pieces, with a small 

 apparently pentagonal canal. 



Height 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, 015 inch. 



This species is related to such forms as .S*. carinalu-i and 5. dichotomiis, Hall ; 

 .S". rusticus, White, and 5. Wacksmuthi, M. and W., but differs from them all too 

 clearly to render a comparison necessary. 



Locality and position. — Upper division of the Burlington group, at Burling- 

 ton, Iowa. Lower Carboniferous. No. 295 of Mr. Wachsmuth's collection. 



ScAPHiocRiNCS scALARis, M. and W, 



Body small, somewhat cup-shaped, being broad below, and a little expanded 

 above ; about twice as wide as high at the top of the first radials. Base small 

 and hidden by the column in the concavity of the under side. Subradial pieces 

 tumid, wider than high, and arranged so that the body rests upon them, when 

 placed on a plane surface with the column removed ; all appearing as if penta- 

 gonal, excepting the two on the anal side, which seem to be hexagonal, but 

 they must all have each an additional obtuse angle at the middle of the under 

 side. First radials about of the same size as the subradials, wider than long 

 and pentaganal in form, though one on the anal side has one side so short as 

 to appear as if quadrangular ; each a little expanded above, so as to present, 

 with the broad excavations at their inferior lateral angles, a more or less con^ 

 stricted appearance. Second radials smaller than the first, rounded on the 

 outer side, and a little constricted on the lateral margins, all wider than long, 

 with a quadrangular outline. Third radial pieces in all but the anterior ray. 

 nearly as'large as the first, but proportionally longer, rounded on the outer, 

 side, constricted in the middle, and pentagonal in form ; the superior lateral 

 sloping sides of each supporting an arm. In the anterior ray the third piece 

 is narrow and long, truncated above, and merely supports a single arm. 



First anal piece smaller than the subradials, pentagonal in form, and resting 

 between the upper sloping sides of the two hexagonal subradials ; connecting 

 on the left with the second anal, and on the right with a first radial, while it 

 supports one side of another anal above. Second anal of nearly the same 

 size as the first, and resting upon the superior truncated side of the subradial 

 below. Above these, two alternating series of anal pieces are seen extend-- 

 ing upward, to connect with the base of the so-called proboscis. 



Arms nine, simple from their origin on the third radials, rather angular on 

 the back, and eacli composed of short wedge formed pieces, arranged some-, 

 what in zigzag, with their longer ends alternately on opposite sides, and pro- 

 jecting so as to support stout, rounded pinnuLT, composed of joints sometimes 

 nearly as long as wide. Pinnulse very regularly arranged, so as to leave in- 

 tervening spaces scarcely of their own breadth, and so stout as to present 

 rather the appearance of armlets, than what are usually called tentacles, in the 

 descriptions of fossil Crinoids ; all like the arms with the ambulacral furrows 

 comparatively deep and large. 



Vault unknown; proboscis (so-called) about half as long as tbearms, com- 

 paratively rather slender until at the upper extremity, where it iS suddenly ex- 

 panded to nearly twice its breadth below, and somewhat fiattene4 onitop. The 



1869.J 10 



