PLATE 131. 



JV.B.— The signification of the characters is the same in all the figures (compare p. 718). 



a. Northern polar spines. 



b. Northern tropical spines. 



c. Equatorial spines. 



d. Southern tropical spines. 



e. Southern polar spines. 



QUADBILONCHIDA. 



Fig. 



1 



Fig. 



2 



Fig. 



3 



Fig. 



4 



Fig. 



5 



Fig. 



6 



Fig. 7. 



Fig. 8. 

 Fig. 9. 

 Fig. 10. 



Quadrilonche mesostaura, n. sp., 



Quadrilonche platystaura, n. sp., . 



Xiphoptera dodecactena, n. sp., 



The central capsule with the central part of the skeleton. 



Lonchostaurus bifurcus, n. sp., .... 



Lonchostaurus crystallinus, n. sp., 



Lonchostaurus rhomboides, n. sp., 



The radial spines are completely enclosed in the rhombic calymma, the 

 surface of which is covered with small plates, similar to those in the 

 shell of the Sphserocapsida. 



Zygostaurus amphithectas, n. sp., 



The square central capsule envelops the half skeleton 



Zygostaurus sagittalis, n. sp., 



Lithoptera tetraptera, n. sp., 



Lithoptera quadrata, n. sp., . 



The central part of the skeleton is enclosed by the four-lobed central 

 capsule. 





Diam. 



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