418 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



DizygOCrinUS facetUS (Miller and Gurlby). 

 Plate XXXIII. Fig. M. 



1890. Batocrinus facetus — Miiler aud Gbbley ; Journ. Ciucia. Soc. Nat. Hist., Vol. XIH. (Authors' 



copy, p. 35), Plate 6, Fig. 8. 



Calyx below medium size, wider than high ; in ornamentation and gen- 

 ei-al appearance resembling D. inclianensis, but having less than half the num- 

 ber of arms. Dorsal cup semiglobose ; the radial plates marked by narrow 

 ridges, which follow the median portions of the plates. Plates convex, 

 covered with irregular strice and small nodes. Suture lines grooved and 

 rather distinct. 



Base very short, circular, almost resembling a stem joint. Radials short, 

 nearly twice as wide as long ; the upper face concave. First costals com- 

 paratively large, quadrangular, as long as the radials but considerably nar- 

 rower ; their upper and lower faces convex. Second costals a little wider 

 but not longer than the first ; heptagonal ; the upper faces obtusely angular. 

 Distichals varying in number ; the anterior ray having three rows, which 

 support the arms ; the antero-lateral ones but two, followed by two fixed 

 palmars. In the two posterior rays, the axillary costal supports upon the 

 side facing the anal interradius two rows of distichals followed by 2 X 2 pal- 

 mars, upon the opposite side three distichals. Arm formula : 1^. Arm bases 

 projecting, directed obliquely upveard, and separated interradially by small 

 interbrachial pieces, which connect with the plates of the ventral disk. 

 Arms single, long, decidedly tapering until quite slender at the tips ; com- 

 posed from the third joint up of two series of rather long joints. Pin- 

 nules extremely long, stout, cylindrical, formed of ten to twelve joints, 

 which are about four times as long as wide. Interradials: 1, 2, 1, and 

 one or two irregular pieces in the arm regions. Anal plate as large as the 

 radials, supporting 3, 3, 2, and 1 plate. Ventral disk depressed conical, 

 the plates tumid and of regular size ; anal tube slender but comparatively 

 long, composed of nearly flat pieces, among which at intervals others are 

 interposed bearing sharp tubercles. Column round ; the nodal joints with 

 rounded, strongly projecting edges. 



Horison and Locality. — Keokuk group ; Canton, Ind. 



RemarJcs. — This species was described as having seventeen arms, which 

 is abnormal, the regular number being sixteen. Neither has it " eleven anal 

 plates." The authors evidently mistook the lateral ends of the arm-bearing 



