PLATE X Continued. 



Pago. 

 DlCEIAOCEPHALUS MARICA 44 



Fig. 13. Enlargement to three diameters of the central portions of the head. 

 Fig. 14. Free cheek, associated with figs. 2 and 3. 



DlCELLOCEPHALUS NASUTU8 40 



Fig. 15. Central portion of the head, showing the glabella and prolonged anterior border 

 of the head. Natural size. 



CHARIOCEPHALUS ? TUMIFRONS 61 



Fig. 16. Specimen showing the frontal margin, and a less protuberant frontal lobe to the 



glabella than in the type of the species, enlarged to two diameters. 



Fig. 6. Pygidium associated with Chariocephalus tumifrons, and supposed to belong to the 

 species. 



PTYCHOPARIA I^EVICEPS 64 



Fig. 17. View of the central portions of the head, enlarged to three diameters, with the pos- 



tero-lateral limbs broken off. 

 18. Free cheek, associated with the heads of this species and P. Oweni. 



DlCELLOCEPHALUS lOLE 43 



Fig. 19. View showing the strongly-marked features of the central portion of the head of 



the species, enlarged to two diameters. 

 Fig. 20. HYPOSTOMA, associated with fragments of a species of the genus Dicellocephalus, 



enlarged to three diameters. 



PTYCHOPARIA . 00 



Fig. 21. Strongly convex hypostoma, associated with Ptychoparia Oweni, enlarged to three 



diameters. 

 Fig. 22. An hypostoma, similarly enlarged, associated with Ptychoparia any i us, P. Oweni, and 



P. IcBviceps. 



PTYCHASPIS MINUTA 60 



Fig. 23. Enlargement to four diameters of a head, showing the glabella, fixed cheeks, ocu- 

 lar ridges, and depressed frontal limb. 



