CLASS III 



CRINOIDEA 



193 



Eucalyptocrinus, and sharing the same distribution in the Silurian ; not known 

 in the Devonian. 



Fig. 293. 

 Callicnmis rodatus (Hising.). Silurian ; Gotlaud. A, Crown. B, Calyx showing the construction of the 

 tegmen. V, Inner or ventral aspect of tlie ba.se. D, Outer or dor.sal aspect of the same. Natural size (after 

 Angelin). 



Chicagocrinus Weller. Like Callicrinus, but the primibrachs (costals) 

 reduced to a single diminutive plate in each ray. Silurian ; North America 

 (Chicago area). 



Family 7. Batocrinidae Waclismuth and Springer. 



Monocyclic. The lower brachials forming an important part of the dorsal cup. 

 Radiais in contad except at the posterior side, where they are separated hy a hepta- 

 gonal anal plate, followed hy three plates in 

 the second ränge. Base hexagonal. Rays 

 usually hranching hy equal hifurcations. 



Subfamily A. Periechocrininae. 



Tegmen composed of numerous small, un- 

 dißerentiated plates. Ordovician to Lower 

 Carboniferous. 



Tanaocrinus W. and Sp. Interbrachials 

 numerous, indefinitely arranged in de- 

 pressed areas passing gradually into the 

 tegmen, leaving brachials in ridges con- 

 tinuing to the free arms ; posterior area 

 divided by median ridge of anal plates 

 resembling brachials. Arms uniserial 

 with ossicles more or less cuneate, tend- 

 ing to interlock distally ; branching be- 

 yond the calyx. Calyx elongate. Basais 

 five. Column round, or sub-pentagonal. 





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294. 



Carboniferous. Analysis 



of calyx ; h, Basals ; li, Radials ; ihr, Interbi-achials ; 

 SX, supplenieiitary anal ; X, Special anal plate 

 (after W. and Sp.). 



Ordovician (Cincinnatian) ; Ohio. 



Xenocrinus^ S. A. Miller. Basals four. Arms not branching. Column 



1 Better speciraens obtained since the preparation of Wachsmuth and Springer's Monograph 

 show clearly not only that the interbrachials in this genus are deflnite plates with close sutures, but 

 VOL. I O 



