170 



ECHINODEEMATA PELMATOZOA 



SUB-KINGDOM III 



Family 4. Eugeniacrinidae. Zittel. 

 (Coadunata, Miller; Holopocrinidae, pp. Jaekel.) 



Dorsal cup composed of Jive (rarely four) thick, rigidly united radials resting 

 upon a centrodorsal ; basals invisible, tegmen unknown. Costals compressed, flange- 

 like ; united by syzygial sutures, or fused 

 with one another. Arms uniserial, robust, 

 and incurving. Stem short, destitute of 

 cirri, and composed of but a few long 

 cylindrical joints with granulated or 

 striated articular faces. Dorsocentral 

 thickened and expanded. Lias to Lower 

 Cretaceous ; Europe. 



Eugeniacrinus, Miller (Fig. 284): 

 Dorsal cup small, saucer-shaped, and 

 with shallow body- 

 cavity. Centro- 

 FIO. 284. dorsal covered with 



Eugeniacrinus caryophyllatus, Mill. Upper Jura ; five radiating ridges. 

 Streitberg, Franconia. o, Calyx with centrodorsal, ^ invisible when the 



seen from one side (nat. size) ; b, c, Ventral and dorsal 



aspects, 3 /2 ; d, d*, First brachial, inner and upper 



surface ; e, Second brachial, seen from the inside (nat. 



size) ; /, h, E. nutans, Goldf. Same locality ; /,/*, First tached, but f rom the 



and second Br fused together, seen from the outside . , , . , 



and inside, respectively ; g, Arm-plate, figured in four COUrSC OI the axial 



positions ; h, Dorsal and lateral aspects of an inrolled 



at 



^ aT1 nla /Fio- 285^ it 



is apparent that 



they are pushed upward so as to be completely enveloped 

 by the E. The latter are very heavy, closely united, and 

 sometimes completely anchylosed. The lateral margins of 

 their upper faces are extended upwards so as to form con- 

 spicuous projections ; the intermediate spaces are occupied 

 by transverse ridges and deep fossae. Costals two, the 

 upper one axillary. Structure of arms unknown. Abun- 

 dant in the Upper Jura, notably in the Spongitenkalk of 

 Southern Germany, Switzerland, France, and the Car- 

 pathians. Less common in the Dogger and Lower 

 Cretaceous of the Alps. 



Jaekel 1 divides Eugeniacrinus into the following sub- 

 genera : Cyrtocrinus, Sclerocrinus, Tetanocrinus, Eugeniacrinus, 

 s. str., and Gymnocrinus. The chief differential characters 

 consist in modifications of the distichals, the arms, and 

 articular surfaces of the radials. 



Eudesicrinus, de Loriol. Stem reduced to two short 

 thick segments which bear the five R directly. Lias. 



FIG. 285. 



Eugeniacrinus caryo- 

 phyllatus, Mill. Upper 

 Jura, o, Restoration, 

 without the arms (after 



Tetracrinus, Miinst. R typically four, rarely three or operfto Bh y 



how the silici- 



five ; apparently reposing dire'ctly upon the column, as no S ke a j al canals 

 B or IB are visible. Upper face of the centrodorsal 

 marked by four (sometimes three or five) prominent ridges which are radially 

 disposed ; lower face bearing about fifteen radiating prominences, which are 



1 Zeitschrift der deutsch. geol. Gesellscli. Bd. XLIIL, 1891. 



