1 i PALAEONTOLOGY OF NEW YORK. 



I* II ACOPID^E. 



PHACOPS, Emmrich. 1839. 

 Phacops cristata. 



PLATE VI, FIGS. US, 16-29; AND PLATE VIII A, FIGS. 1-4. 



1 1 istata, Hall. Descr. New Species of Fossils, etc., p. 67. 1861. 

 Phn, .Hall. Descr. New Species of Fossils, etc., p. 67. 1861, 



a, II u.l. Fifteenth Rept, N. Y. State Cab. Nat, Hist., p. 95. 1862. 

 . Hall. Fifteenth Rept, N. Y. State Cab. Nat. Hist., p. 95. 1862. 

 tta, Hall. Illustrations of Devonian Fossils, pi. vi, tigs. 1-13, 16, 17. 1876. 

 Phacops bombifrons, Hall. Illustrations of Devonian Fossils, pi. vi, fig-s. 18-29. 1876. 



ral Form ami Proportions. Outline elongate, sub-elliptical. Length to 

 width as 1.7 to 1. Lateral margins sub-parallel. 

 Surface depressed-convex, echinate along the axis. 



Cephalon broadly ovate or nearly semi-circular in outline; length to width as 

 1 to 7. Frontal area obsolete, lateral area narrow, margins broadly thickened 

 by doublure, and produced at the genal angles into short blunt spines, which 

 air directed slightly upward and inward. Sub-marginal sulcus strong, ex- 

 tending to within a short distance of the genal extremities, bearing on the 

 lateral margins, behind the epistoma, ten or eleven crenulations which 

 diminish in size backward. Epistoma comparatively narrow. 



Facial Sutures not observed. 



Glabella broad, convex, sub-pentagonal, tumid (generally flattened in ex- 

 am pic- from the Schoharie grit), protuberant, extending for one-third its 

 length beyond the frontal margin. In favorably preserved specimens, either 

 of the external or internal surface, traces may be seen of the first and second 

 pair of lateral furrows ; third lateral furrows deeply impressed but undefined, 

 making the third or basal lobes of the glabella very obscure. Antero-lateral 

 furrows may sometimes be discerned in front of the first pair of lateral fur- 

 rows, and parallel to the palpebral sulci. 



Occipital furrow broad and deep; occipital ring elevated and conspicuous. 



