210 



ECHINODERMATA— PELMATOZOA 



PHYLUM IV 



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

 canals. Devonian. Eepresented hy a single genus, which probably does not 



belong to this suborder, but 

 whose systematic affinities have 

 not been satisfactorily deter- 

 mined. 



Cupressocrinns 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 ; tliese are probably 

 modified orals, and served in 

 part for the attachment of 

 muscles. Five round aper- 

 tiires, through which the 

 ambulacra entered the calyx, 

 perforate the divisions between 

 the consolidating plates ; one 

 of the latter is pierced by the 

 anal opening (Fig. 311, e). 

 Arms provided with a wide 

 and deep ventral furrow, lined 

 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. 



Eifel. 



' Fig. 311, 



Cupressocrinus crassua Goldf. Devonian ; Gerolstein 

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

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

 showing plated covering of ambulacral furrows, and dorsal canals 

 perforating the ossicles ; e, Interior of calyx from above, showing 

 the live consolidating jjlates, the lowermost containing the anal 

 opening ; /, Radial pierced by ambulacral opening, but with wall 

 covering the same partly broken away ; g, Side-view of radial in 

 which the ring-like covering of the ambulacral opening is pre- 

 served intact. 



Suborder 2. FISTULATA Wachsmutli and Springer. 



Tegmen composed of numerous plates, consisting either of orals with supra-tegminal 

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

 entiated plates without identifiable orals or amhulacrals. Posterior interamhulacrum 

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

 jpinnulate or non-pinnulate, 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 develoj)ment of the 

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

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

 the posterior one being often perforated (madreporüe). In the latter the extension involves 

 alraost 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 position of the anal opening, 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 families the radials are transversely bisected in one, two, or three 

 rays, producing Compound 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 



