PLATE XX. 
Proetus angustifrons. 
Page 91. 
See Plate 22. 
Eig-. 1. A portion of the cephalon, showing-the glabella. The crust is mostly broken away, and the base 
of the glabella is made too wide in the drawing. 
Schoharie grit. Albany county. 
Fig. 2. The pygidium. The drawing fails to represent the faint grooves on the pleural annulations. 
Schoharie grit. Albany county. 
Fig. 3. Pi-olile view of a smaller pygidium, enlai-ged to two diameters. 
Schoharie grit. Albany county. 
Pig. 4. A small pygidium, showing a slight emargination at the- posterior extremity. Enlarged to two 
diameters. 
Fig. 5. Protile view of the same. 
Schoharie gi-it. Albany county. 
Proetus Conradi. 
Page 89. 
See Plates 21 and 22. 
Fig. 9. A pygidium of avei-age size retaining the crust, and enlarged to two diameter.s. The pleural 
annulations are i-arely so distinct as in this figure. 
Schoharie grit. Albany county. 
Proetus canaliculatus. 
Page 107. 
See Plate 23. 
Fig. 10. The glabella and fixed cheeks enlarged to two diametei-s. The faint first pair of glabellar fui-- 
rows is not i-epresented in the drawing. 
Fig. 11. Profile view of the same. 
Corniferous limestone. Falls of the Ohio. 
Proetus clarus. 
Page 104. 
See Plate 22. 
Fig. 12. A nearly entire individual, natural size. 
Fig. 13. Profile view of the same. 
Coraiferous limestone. Stafford, Genesee county. 
Fig. 14. A small individual, showing a somewhat broadei- border and longer cheek-spines. Enlai-ged to 
two diameters. 
Corniferous limestone. Stafford, Genesee county. 
Proetus Hesione. 
Page 93. 
Fig. 1.5. The pygidium on which this species was established, showing the greater length and tnore nu¬ 
merous annulations than in associated species. 
Fig. 16. Profile view of the same. 
Schoharie grit. Schoharie, Schohane county. 
