136 



ECHINODERMATA PELMATOZOA 



SUB-KINGDOM III 



Triacnnus, Miinst. (Fig. 237, B}. Differs from the preceding in having but 

 three B. Wachsmuth has shown, however, that some of the Eifel specimens 

 occasionally have five B, thus leading to the inference that the two forms are 

 identical. Devonian ; Eifel, Fichtelgebirge. 



Family 4. Symbathocrinidae. Wachsmuth and Springer. 



Calyx small, bowl-shaped, composed of three unequal or of Jive equal basals, and Jive 

 nearly equal radials. Tegmen foi'med by five small, asymmetrical orals ; between these 

 and the radials extends a long, anal tube, which, however, is not supported by anal 

 plates. Entire upper edges of the radials bevelled off so as to form straight articular 

 facets, which are furnished with well-developed transverse ridges. Arms five, simple ; 

 column round. Devonian and Carboniferous. 



Symbathocrinus, Phill. B three, unequal ; R five, long, quadrangular or 

 pentagonal. The posterior oral larger than the others. Anal tube long, very 

 slender, resting partly upon the radials and partly upon the orals. Arms long, 

 uniserial, and composed of comparatively thick ossicles with sharp angular edges. 

 Carboniferous ; Great Britain and North America. 



Phimocrinus, Schultze. Differs from the preceding in having five B. De- 

 vonian ; Europe. 



Stylocrinus, Sandb. Distinguished from Symbathocrinus mainly by the 



character of the radial facets, 

 which are directed obliquely 

 downward and inward, in- 

 stead of upward and outward. 

 Devonian. 



Storting ocrinus, Schultze. 

 Devonian. Lageniocrinus, de 

 Kon. Carboniferous. 



Family 5. Cupressocrinidae. 

 d'Orbigny. 



Calyx large, basin - shaped, 

 composed of five equal basals and 

 Jive equal radials ; the basals en- 

 closing a central pentagonal plate, 

 which in all probability represents 

 Jive anchylosed infrabasals. Upper 

 faces of radials broad, truncate y 

 and forming an even horizontal 

 line. Costal s compressed, flange- 

 shaped. A peculiar annular 



showing well- preserved ' inrolled pinnules, plated covering of structure, the SO-Cttlled " COnSOlidat- 



ambulacral furrows, and neuro-vascular canals perforating the . 



ossicles ; e, Interior of calyx from above, showing the five con- ing apparatus, Situated OU lite 

 volidating plates; the lowermost containing the anal opening- , / n 7 



/, Radial pierced by ambulacral opening, but with wall covering, U PP^' interior margin OJ me Ctt/yj' 



the same partly broken away ; 0, Side-view of radial in which the bffwffn HIP nvrn hnw<i Arm* 



ring-like covering of the ambulacral opening is preserved intact. mn tfl6 a1 m ~ 0aSeS - A 1 MS 



five, simple, uniserial, and closely 



folded ; they are composed of broad thick plates united by close sutures, and are 

 traversed by a well-developed dorsal canal Column pierced by a large axial and 

 three, four, or five peripheral canals. Devonian. 



F IG> 238. 



Cupressocrinus crassus, Goldf. Devonian; Gerolstein, Eifel. 

 a, Perfect specimen, natural size; 1), Cross-section of column ; 

 c, Centrodorsal plate; d, Section through the folded -up arms, 



