204 



ECHINODERMATA ASTEBOZOA 



Sub-Order 3. EUOPHIUREAE. 



SUB-BRANCH II 



Arms with dorsal, lateral, and ventral shields. Mouth shields well developed, 

 one of them serving as a madreporite. Devonian to Eecent. 



FIG. 



Aspidura loricata, Goldf. sp. Muschelkalk ; Waschbach, Wurtemberg. A, Group of individuals of the 

 natural size (after Quenstedt). B, Ventral aspect enlarged (after Pohlig). 



The Ophiuroids of the Mesozoic 

 era are closely related to recent forms, 

 and are all assignable to families now 

 in existence. Most of them have but 

 two bursal fissures in each interradium ; 

 but the genus Ophiura, Lam. (Ophio- 

 derma, M. and T.), has four in each 

 interray, and is represented as early 

 as the Trias (0. Hauchecorni, Eck : 

 Muschelkalk. 0. Egertoni, Brod. sp. ; 

 Lias). 

 FIG. 33i. The genera Aspidura (Fig. 330) 



Ophiocten Kelheimense, Bohm. Lithographic Slates ; arif l /Jrriirn Acra<55i7 arp orrasionallv 

 Kelheim, Bavaria. A, Ventral aspect of disk, enlarged. anQ ^^^^ AgaSSlZ, are 



B, Dorsal surface of one of the arms. (Both figures abundant in the German Muschelkalk, 



enlarged ; original in Munich Museum.) , T . . -. , . -, 



and certain Liassic Ophmrans also 



FIG. 332. 



Geocoma carinata, Goldf. Lithographic Slates ; Zandt, near Solenhofen, Bavaria. A, Individual of the 

 natural size. B, Dorsal aspect of disk, showing granulations and central depression. C, Ventral surface of one 

 of the arms. (Figs. B and C enlarged.) 



lived in herds. In the Lower, Middle, and Upper Jura are found forerunners 



