210 



ECHINODERMATA— PELMATOZOA 



PHYLUM IV 



dorsal canal. Column pierced hy a large axial and three, four or five peripheral 

 canals. Devonian. Represented by a single genus, which probably does not 



belong to this suborder, but 

 whose systematic affinities have 

 not been satisfactorily deter- 

 mined. 



Cupressocrimis Goldf. (Fig. 

 311). Tegmen flat ; the greater 

 part of it occupied by the so- 

 called consolidating apparatus. 

 This is composed of five 

 petaloid, horizontally trun- 

 cated interradial pieces, which 

 are laterally in contact, and 

 enclose a large, central open 

 space ; these are probably 

 modified orals, and served in 

 part for the attachment of 

 muscles. Five round aper- 

 tures, through which the 

 ambulacra entered the calyx, 

 perforate the divisions between 

 the consolidating plates ; one 



showing plated poveiiiig of ambiilafial furrows, and doisal canals of the latter is pierCCd by the 

 perforating the ossicles ; f, Interior of calyx from above, showinfc -i • /j-\- qt'i \ 



the five consolidating plates, the lowermost containing the anal anal Opening (^r Ig. oil, C). 



opening ;/, Radial pierced by ambulaeral opening, but with wall A«Tna nrnvirlprl witVi a wirlp 



covering the same partly broken away ;./, Side-view of radial in -^imt. piUVlUtiU Wltu d. Wiue 



which the ring-like covering of the ambulaeral opening is pre- aii(| cleCD Ventral furrOW, lined 

 served intact. '- , . . . , 



on both Sides with jointed, 

 closely abutting appendages ; of these there are several to each arm-plate, 

 thus showing that they are different from true pinnules. Middle Devonian ; 

 Eifel, Harz, Nassau and Westphalia. 



Fig. 311. 



Cu'pressocrlnus o-asxjt.s Goldf. Devonian ; Gerolstein, Eifel. 

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

 c, Fused infrabasals ; d, Section through the folded-up arms. 



Suborder 2. FISTULATA Wachsmuth and Springer. 



Tegmen composed of nmnerous plates, consisting cither of orals with supra-fegminal 

 ambulacra passing over their edges, and interamlmlacra, or of more or less undiffer- 

 entiated plates without identifiable orals or ambulacrals. Posterior inter amhidacrum 

 usually more or less extended into a strongly plated anal tube or ventral sac. Arms 

 pinnulate or non-pimiulafe, usually uniserial, but biserial in some later genera. Base 

 monocyclic or dicyclic. Ordovician to Trias. 



The Fistulata are characterised, in their typical genera, by a great development of the 

 jiosterior interradins, which is extended upward in the form of an anal tube or a ventral sac. In 

 the former case the anus is at the distal end ; orals are moie or less represented in the tegmen, 

 the posterior one being often i)erforated {'nuidrejiorite). In the latter the extension involves 

 almost the entire tegmen ; the plates of the sac are often perforated by small, round or slit- 

 like pores (respiratory pores) ; all traces of orals are lost ; and a curious reversal takes place 

 in the jiositiou of the anal oi)ening, which, instead of being at the distal end, or posterior, is 

 on the anterior side of the sac, either at the base, or part way up, sometimes through a 

 lateral spout. 



In some of the early fimilies the radials are transversely bisected in one, two, or three 

 rays, producing comiiound radials, as in some Larviformia. When three radials are thus 

 compound they are usually in the right posterior, and right and left anterior rays ; but when 

 there is only one, it is constantly that to the right of the anal area, the right posterior. The 



