PLATE LXIV. 



Page. 

 Fig. 1. Ptyehoparia (i.) ivisconsensis , 461 



1. Central portions of head and side outline of median section of head and occipital 



spine. 

 la. Free cheek associated with fig. 1. 

 16. Central portions of head of specimen from the St. Croix sandstone of Wisconsin. 



After Hall, 

 lc. Pygidium from the St. Croix sandstone of Wisconsin. 

 Fig. 2. Ptyckoparia ( ?) diademata 462 



2. Central portions of head. 



2a. Free cheek associated with fig. 2. 

 2b. Hypostoma, associated with fig. 2. 

 2c. Pygidium from the St. Croix sandstone of Wisconsin. 

 Fig. 3. Ptyehoparia sp. undet 458 



3. Central portion of head, x 3. 



Fig. 4. Ptyehoparia Uanoensis 458 



4. Reproduction of illustration of the type specimen. 



Fig. 5. Ptyehoparia sp. undet 458 



5. Central portion of head of the only specimen in the collection. 



Fig. 6. Bathyiiriscus sp. undet 466 



6. Figure of the specimen referred to in the text. 



476 



