PLATE 79. 



Page 



Fig. 1 - 14. ACIDASPIS TUBERCOLATUS. 368 



1. View of a specimen preserving the members in connexion; but the fossil being imbedded 



in a hard stone, the condition does not admit of the parts being sliown in detail. 

 1 o. The counterpart of fig. 1, showing the extensions of the lateral spines and the form of the 

 pygidium. 



2. The central portion of the head, showing the lobes of the glabella, the frontal border, the 



occipital annulation, and the central posterior spine. 



3. The central part of the head of another specimen. 



6. A portion of the surface enlarged. 



6 & 7 . The right cheeks of two different individuals, preserving the eye tubercle, and showing 

 differences in the exterior and inner spines. 



8. The left cheek, which shows very distinctly, as do the others, the gradation of the border 

 ornaments, from small nodes at the anterior extremity, to distinct spines. 



8 ff. A cheek, with the eye tubercle, enlarged. 



9 ft 10. The underside of two cheeks, one of which shows a single spine on the inside, and the 



other a single spine with the rudiments of two others above it. 



11. An aiticulation of the thorax. 



12. The underside of a part of the thorax, showing the extensioB of the lateral gpines of the 



articulations. 



13. The pygidium, in which the upper lateral spine is not fully developed. 



14. The pygidium of another individual, showing the parts described. 



Fig. 15 - 19. ACIDASPIS HAMATA. 371 



15. A small individual preserving the central portion of the head and the occipital spine. 



16. A larger individual. 



17. Profile view, showing the recurved spines. 



18. The bifurcating occipital spine of a larger individual. 



19. A fragment of the thorax, and the pygidium, probably of this species. 



19 o. A fragment of the thorax of a large individual, showing the prolongation of the lateral 

 lobes into spines. 



