240 



ECHINODERMATA— PELMATOZOA 



PHYLUM IV 



authors) (Figs. 344, 345). Dorsal cup small, saucer - shaped, and with 

 shallow body-cavity. Proximale covered with five radiating ridges. B 

 invisible when the proximale is attached, but from the course of the axial 

 canals (Fig. 344) it is apparent that they are pushed upward so as to be 

 completely enveloped by the B. 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 conspicuous projections ; the inter- 

 mediate spaces are occupied by transverse ridges and deep fossae. Costals 

 two, the upper one axillary. Structure of arms 

 unknown. Abundant in the Ui^per Jura, notably 

 in the Spongitenkalk of Southern Germany, 

 Switzerland, France and the Carpathians. Less 

 common in the Dogger and Lower Cretaceous of 

 the Alps. 



Tetracrinus Miinst. B typically four, rarely 

 three or five ; apparently reposing directly upon 

 the column, as no B or IB are visible. Upper 

 face of the proximale marked by four (sometimes 

 three or five) prominent ridges which are radially 



Fig. 344. 



Euiieniacriiius airyophyllat'us Miller. Upper Jura ; 

 Streitberg, Franconia. a, Calyx with eentrodorsal, 

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

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

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

 size), f-h, E. nutans Goldf. ■ Same locality ; /, /*, First 

 and second Br fused together, seen from the outside 

 and inside, respectively ; g, Arm-plate, figured in four 

 positions ; /(, Dorsal and lateral aspects of an inrolled 

 arm. 



Fig. 345. 



Eugeniacrinus caryophyllatus 

 Miller. Upper Jura, a. Restora- 

 tion, without the arms (after 

 Fraas) ; b, Calyx broken open to 

 show the silicifled axial canals 

 (after Jaekel). 



disposed ; lower face bearing radiating peripheral striae, which are not con- 

 tinued over the median portion of the plate. B with transverse ridges and 

 large muscular fossae. Stem-joints barrel-shaped. Upper Jura ; Europe. 



Gammarocrinus Quenst. {Sderocrinus Jaekel). Dorsal cup massive, concave 

 below. Upper Jurassic ; Europe. 



Gymnocrinus Loriol. First axillary remarkably developed. Upper Jura ; 

 Europe. 



Phyllocrinus d'Orb. Dorsal cup globose ; B with narrow articular facets, 

 at either side of which are long, upright projections. Upper Jura and Lower 

 Cretaceous, notably in the Mediterranean district. 



Torynocrinus Seeley (Cyrtocrinus Jaekel ; (?) Hemicrinus d'Orb.). Dorsal 



