EXPLANATIONS OF PLATE 22 (13). 



Ill^nus armatus. page 330 (26). 



Figs. 1, 2. Upper and profile views of the head of a well-preserved individual. 

 " 3. The pygidium and last thoracic segment, found associated with the head and 

 supposed to be of the same species. 



Ill^nus ioxus (n. s.). page 378. 



= IllvEnus barriensis. page 332 (28). 



Figs. 4, 5. Profile and upper views of the head of a small individual. 

 " 6-8. Upper, lower and profile views of a medium sized individual. Fig. 7 shows 



the extent of the infolding of the border, and the direction of the suture on 



the under surface. 

 '' 9. The movable cheek of a large specimen. 

 " 10. A pygidium of the form commonly found associated with the other remains 



referred to this species. 

 '^ 11. A small glabella, referred with doubt to this species. 



Ill^nus cuniculus. page 377. 



Fig. 12. View of the glabella. 



IlljENUS insignis. page 831 (27). 



Fig. 13. The glabella and fixed cheeks, with the movable cheeks restored in outline. 

 *' 14. The pygidium referred to this species. 



Ill^nus imperator. page 332 (28). 



Fig. 15. The head of a large individual. The figure is reduced to one half the natural 

 size. 

 '' 16. The pygidium of a very small specimen of the species. 



" 17. The pygidium and parts of four of the thoracic segments, reduced in size to 

 the same degree as fig. 15. 



