PLATE XXII. 
PrOETUS ANGUSTIFRONS. 
Page 91. 
See Plate 20. 
Fig. 1. The intra-sutural portion of the cephalon, retaining the crust, showing the form of the glabella, 
the sloping frontal border and preserving indications of three pairs of lateral fui-rows. Enlarged 
to two diameters. 
Schoharie grit. SeJiolmrie, Schoharie county. 
Fig.' 2. The movable cheeks, preserving the visual surfaces of the eyes, showing the character of the genal 
spines and the direction of the suture upon the frontal doublure. Enlarged to two diameters. 
Schoharie grit. Near Clarksville, Albany county. 
Fig. 3. A small pygidium showing the distinctly sulcate and finely tubei’cled annulations, and the broad, 
smooth boi’der. Enlarged to two diameters. 
Schoharie gi-it. Near Clarksinlle, Albany county. 
Pkoetus Conradi. 
Page 89. 
See Plates 20 and 21. 
Fig. 4. A pygidium, showing the general convexity and the sloping borders. The lateral annulations, 
which are usually quite indistinct in this species, have been given too much prominence in the 
■ drawing. Enlarged to two diameters. 
Schoharie grit. Schoharie, Schoharie county. 
PrOETUS, S[). 
Page 94. 
Fig. 5. An imperfect cephalon retaining a portion of the crust and showing a more convex glabella and a 
broader and flatter border than in either of the foregoing species. Enlarged to two diameters. 
Schoharie gi-it. Schohar-ie, Schoharie county. 
Fig. 6. An internal cast of a pygidium which differs from that of the pi-eceding species in the fewer annu¬ 
lations. Enlarged to two diametei s. 
Schoharie grit. Knox, Albany county. 
Probtus latimaroinatus. 
Page 97. 
Fig. 7. A large glabella, natural size, showing the lateral furrows and the broad, flat fi-ontal border. 
Schoharie grit. Pendleton, India,na. 
Fig. 8. The left movable cheek i-eferred to this species. 
Schoharie gi'it. Pendleton, Indiana. 
Fig. 9. The right movable cheek. 
Schoharie grit. Pendleton, Indiana. 
Fig. 10. A very imperfect individual, indicating the form and proportions of the body. 
Schoharie grit. Pendleton, Indiana. 
Fig. 11. The pygidium, showing the essential characters of this part of the body. 
Schoharie grit. Pendleton, Indiana. 
Fig. 12. The pygidium and a portion of the thoi-ax of a large individual. 
Schoharie grit Pendleton, Indiana. 
PrOETUS CURVIMARGINATUS. 
Page 94. 
Fig. 13. A somewhat imperfect example, retaining a portion of the crust and showing the relative pro- 
poi'tions of the species. 
Schoharie grit. Pendleton, Indiana. 
Fig. 14. The intra-sutui-al portion of a cephalon, showing the conate form of the glabella, the i-ecurved 
frontal border and the four pairs and the accessory pair of latera,! furrows. 
Fig. 15. Outline profile of the same, showing the elevation of the glabella and the curvature of the border. 
Schoharie grit. Pendleton, Indiana. 
Fig. 16. A smaller, imperfect individual drawn from a gutta-percha impression from a natui-al mould of the 
internal surface in the sandstone. 
Schoharie grit. Pendleton, Indiana. 
Fig. 17. A small pygidium, showing the character of the annulations and the curvature of the border. 
Schoharie grit. Pendleton, Indiana. 
