150 



ECHINODERMATA— PELMATOZOA 



PHYLUM IV 



Fig. 234. 



Aristocystites boheinicut;] Barr. Ordovician (,Dd-i) ; Zahorzan, 

 Bohemia, a, Side view ; h, Sumniit aspect (after Banande). ^^ 



Order 1. AMPHORIDEA Haeckel (pars). 

 No radial symmetry in food grooves or calyx plates. . 



Family 1. Aristocystidae Neiimayr. 



Calyx composed of mmierous plates without regular arrangement. No extension 



of food-grooves or brachial processes. Stein undeveloped, 

 or very short. Cambi'ian to Silurian. 



Pilocystites, Lapillocystites and Acanthocystites Bar- 

 rande. Cambrian ; Bohemia, These are obscure genera. 

 Aristocystites Barr. (Fig. 234). Calyx bursiform 

 or ovate ; ventral surface with four apertures ; stem- 

 less. Ordovician ; Bohemia. 

 & Deutocystites Barr. Ven- 



tral surface with three aper- 

 tures. Calix Rouault {Cra- 

 terina Barr.). Conical, trun- 

 cate. Baculocystites Barr. 

 Ordovician ; Bohemia. 



Megacystifes Hall (Holocystis 

 S. A. killer). Elongate, 

 cylindrical or sub-cylindrical ; 

 short - stemmed or stemless, 

 with subcentral mouth. Silur- 

 ian ; North America, Gotland. 

 ? Lodanella Kayser. Devonian ; Germany. Said to be a sponge. 



Family 2. Anomalocystidae Meek. 



Calyx oval, more or less compressed, with dissimilarly plated broad sides 

 either imperforate or loith simple pores ; pore-rhombs absent. 

 Food-grooves extended in one or more processes. Stem short, 

 tapering, of polymeric columnals. Cambrian to Silurian. 



Trochocystites Barr. (Trigonocystis Haeckel). Calyx 

 strongly compressed. Plates of the right and left sides 

 large, those of both the anterior and posterior small, 

 polygonal. All plates perforate, but without pore- 

 rhombs. Ventral surface with three apertures. Stem 

 composed of several vertical rows of plates. Cambrian ; 

 Bohemia, Spain, Northern France. 



Mitrocystites Barr (Fig. 235). Like the preceding, 

 except that one side of the calyx is composed of toler- 

 ably large, and the other of small plates. Ordovician ; 

 Bohemia. 



Mitrocystella, Bhipidocystis Jaekel. Ordovician ; 

 Bohemia. 



Anomalocystites Hall (Atdeocystites Bill. ; Platycystis 

 S. A. Miller ; Enopleura Weth.). Calyx plates smaller and more numerous 

 on the convex side than on the concave. Anus situated very low down on 



Plates 



Fig. 235. 



Mitrocystites mitra Barr. 

 Ordovician ; Wosek, Bohemia. 

 Supposed right side (after 

 Jaekel). 



