CLASS III 



CRINOIDEA 



237 



Freminville {GanymedAi Gray ; Hihernula Fleming ; Phytoorinus Bio.) (Fig. 

 283) ; Compsometra, Toxometra and Iridometra A. H. Clark, etc. 



Fossil Comatulid Genera. 



The following genera are based wholly or in part upon fossil Comatulids : 

 AUionia Michelotti ; Asteriatites Schlotheim ; Astrocoma Blainville ; Comatu- 

 lina d'Orbigny ; Comatulithes 

 von Schlotheim; Comaturella 

 Miinster; Decacnemos'Evonn; 

 Decameros d'Orbigny, Geo- 

 coma 0. Fraas; Glenotremites 

 Goldfuss; Hertha Hsigenow, 

 Microcrinus Emmons ; Ophi- 

 urites von Schlotheim; Ptero- 

 coma L. Agassiz ; Solanocrinus 

 Goldfuss (Fig. 340). 



The specimens upon 

 which the type species of 

 these genera are founded are 

 rarely well enough pre- 

 served to admit of reference 

 to any one of the Eecent 

 genera, or even families, and 

 in some cases it is doubtful 

 whether they are Coma- 

 tulids at all. P. H. Car- 

 penter attempted to differ- 

 entiate the fossil types into 

 Antedons and Adinometras ; 

 but recent discoveries have 

 shown that the endocyclic 

 and exocyclic forms are 

 by no means easy to dis- 

 tinguish, even with perfect 

 specimens, and with even 



the best Dreserved fossils J"''^; Streltberg, Franconia; b, Ventral; c, dorsal ; and d, lateral 

 Liic uc jj ^ aspect of calyx ; e, Arm-plate. 



the separation of the species 



on this basis is very unsatisfactory. A common method of procedure in 

 dealing with fossil Comatulids has been to refer them all (except those with 

 five arms, all of which belong to the genus Eudiocrinus of the Zygometridae) 

 to a single genus, for which the name Solanocrinus is used. 



e' 



Fig. 340. 



a, Siilanocrimis cnstatiis Goldf. Upper Jura (Dicer.is-Kalk) ; Kel- 

 heiiii, Bavaria. Dorsal aspect of crown ; centrodorsal and xiinuules 

 not preserved (slightly reduced) ; h-d, S. scrohiculatus Goldf. Upper 



Family 5. Plicatocrinidae Zittel. 



Basal circlet funnel-shaped, quadrangular, pentagonal or hexagonal, composed of 

 three (usually), or five bascds which may be solidly anchylosed. Badials four, five, 

 six or eight (rarely seven), long and thin, bearing the post-radial series of brachials 

 on a narrow facet, which occupies only a small portion of their distal edge. Arms 

 long, undivided or branching one or more times ; the first branching iisualhj on the 



