PLATE X. 

 Dalmanites (Chasmops) anchiops. 



See Plate 9. 

 I.'j^r i. An imperfect eephalon. retaining a portion of the (■rust. 



Corniferous limestone. Falls of the Ohio. 

 Fig'. 2. A. large pygidium, in the condition of an internal cast, from which the doublure and spine have 

 I ii removed. This figure is from a plaster cast of Green's original of Aaaphus laticostatus. 



Schoharie grit. Ulster county. 



Fig. '.i. A small pygidium, retaining tl rust ami showing oblique rows of nodes on the pleurae. 



Fig. -1. The same, enlarged one diameter. 



Schoharie grit. Schoharie, Schoharie county. 

 Fig. :">. A small pygidium, retaining the crust ami bearing an unusually long caudal spine. 



Schoharie grit. Schoharie, Schoharie county. 

 Fig. 6. A larger pygidium. 



Schoharie grit. Schoharie, Schoharie county. 

 Fig. 7. A pygidium, from which the tail-spipe has been broken. 



Oriskany sandstone. From tin ciciiiity of DeCewville, Province of Ontario. 

 Fig. 8. A large pygidium. 

 Fig. '.). Profile of the same, showing the curvature and elevation of the spine. 



Schoharie grit. Schoharie, Schoharie county. 

 Fig. 10. A small pygidium, preserved as an internal cast, and showing the impression of the doublure ami 

 spine. 



Schoharie grit. Knox, Albany fount;/. 

 Fig. II. An enlargement to six diameters of the anterior extremity of the head represented on Plate 9, 



fig. 4, to show the crenulation of the frontal border. 

 Fig. 12. A very large imperfect pygidium restored in outline. 



Schoharie grit Schoharie, Schoharie county. 

 Fig. I:!. A targe, nearly entire pygidium, showing the tendency to duplication in the pleural annulations. 



Schoharie grit. Schoharie, Schoharie county. 



Dalmanites (Chasmops) anchiops, var. akmatus. 

 See Plate 9. 

 Fig. 1 1. A restoration in outline of the entire animal, from the eephalon figured on Plate 9, Fig. 8. 



