1881.] NATURAL SCIENCES OF PHrLADELPHIA. 291 



several additional points, and suftlciently, so to make it an inde- 

 pendent genus. 



Technocrinus differs from Mariacrinus, as now amended, in 

 having 1 X 10 secondary radials, instead of 3-4 X 10, and these 

 connected laterally without the, interposition of interaxillaries ; 

 in having the arms given off in an almost continuous ring around 

 the body, and not in clusters ; in the straight upward direction of 

 all the arms, contrary to 3Iariacrinus in which the outer arms are 

 given off obliquely, and only the inner ones run parallel with each 

 other ; in that its arms are strong, simple, composed of single 

 joints, instead of being slender, branching and double jointed. It 

 further differs from Melocrinus in giving off the arms straight 

 and directly from the body, instead of obliquely from the free rays ; 

 in the absence of interaxillaries, and in other minor characters. 



Generic Diagnosis. — Form of calyx similar to Melocrinus. 

 Symmetry, except in the basal portions, perfectly pentahedral. 



Basals four, one of them larger and placed longitudinally in 

 line with the primary radials of one of the lateral rays. Primary 

 radials 3X5; the first two hexagonal ; the third pentagonal and 

 supporting 1X10 large secondary radials, which are all axillarj^, 

 each supporting 2X2 tertiary radials, of which the upper part 

 of the second row is laterally disconnected and free. They are 

 succeeded by several wedge-form plates, which gradually interlock, 

 and which are followed, rather abruptly, by two series of narrow, . 

 alternately arranged arm plates. The arms are long, simple, 

 straight, placed around the body in a continuous ring, and at 

 almost equal distances from each other. Pinnules apparently 

 thin, thread-like, their sides abutting. 



Interradials three to four ; the first resting against the oblique 

 upper sides of the first radials, and between the second. Anal 

 area, so far as known, not distinct from the other interradial 

 ones. Construction of the vault unknown. Column round. 



Geological Position^ etc — Technocrinus has been found only in, 

 the Oriskany Sandstone of Maryland. 



*1859. Technocrinus Andrews! Hall. (Type of the genus.) (Mariacr. — Technocr 



—Andrews!.) Paleont. N. York, iii, p. 141, PI. 86, figs. 1-4. Oriskany 



Sandstone. Cumberland, Md. 

 *1859. Technocr. spinulosus Hall. (Mar!aor. — Technocr. — spinulosus.) Paleont.. 



N. York, iii, p. 140, PI. 85, figs. 1-18. Oriskany Sandstone. Cumberland, Md. . 



(Mariacr. — Technocr. sculptus and T. striatus Hall, are known from the 



basals only). 



