EXPLANATIONS OF PLATE 21 (12). 



\ 



Leperditia fonticola. \ page 335 (31). 



Figs. 1-3. Enlarged views of three different individuals, showing some variations in the 

 proportions and also in the nodes of the siiifabe. 



Sph^rexochus romingert. page 334 (30) and 375. 

 Figs. 4, 5. Two views of a glabella of this species, natural size. 

 " 6. Profile view of the glabella and movable cheek of a small specimen. The flo-ures 



are enlarged to three diameters. 

 •' 7. The pygidium enlarged to two diameters. \ I 



AciDASPis DANAi vel IDA. 1 \ page 333 (29). 



Fig. 8. A specimen preserving the glabella and portions oi the movable cheeks. The 

 figure is of the specimen originally described. 

 " 9. Figure of another individual, showing some modificaions in the lateral lobes of 

 the glabella. This figure was made from a giitta-jercha cast communicated 

 by Prof. WiNCHELL under the name of ^. ida. 



Ceraurus niagarensis. page 376, 



(C. iNSiGNis.) page 335 (31). 



Fig. 10. The glabella and part of one of the fixed cheeks of aipecimen of this species. 



" 11. The hy]>ostoma of this species ? from a specimen inthe collection of Prof, 



WiNCHELL. 



LiCHAs breviceps ? pa^ 334 (30) and 377. 



Fig. 12. The glabella and movable cheek ol a specimen fror Bridgeport, Illinois 

 enlarged to two diameters. 

 " 14. An enlarged figure of the lower surface of a pygidium, ccurring in the same 



specimen with the head. 

 '• 13. Figure of the internal cast of a pygidium ; natural size, Vrafton, Wisconsin. 



Encrinurus nereus. page 375. 



(Encrinurus .) page 334 (30). 



Fig. 15. Figure of the pygidium of this species enlarged to two diiieters. 



Dalmania vigilans. page 35 (31) and 375. 



Fig. 16. View of the head of a specimen denuded of the eyes. 

 " 17. Profile view of another specimen, preserving the cast of ti eyes, the crust 



having been dissolved. 

 " 18. Cast of a pygidium of this species. 



Bronteus acamas. »ge 332 (28). 



Fig. 19. Cast of the glabella of this species, natural size. 

 " 20. The pygidium natural size, but slightly restored on one margii 



