CRUSTACEA. 
19 
In the Corniferous limestone at the Indian quarries, Onondaga county; East¬ 
man’s quarry, Waterville, Oneida county ; Howell’s quarry, Lime Rock, Genesee 
county. Variety pzpa. In the Corniferous limestone everywhere; especially 
abundant in the central and western outcrops at Waterville, Oneida county; 
Phelps and Clifton Springs, Ontario county ; LeRoy and Lime Rock, Genesee 
county; Clarence and Williamsville, Erie county, and in the boulders of decom¬ 
posed chert in Ontario county; Falls of the Ohio. Also at Walpole and North 
Cayuga, Province of Ontario. 
Phacops eana. 
PLATE VII, PIGS. 1-11 ; PLATE VIII, FIGS. 1-18; and PLATE VIII A, FIGS. ‘21-33. 
Calymene hufo, var. rana, Green. Monograph of the Trilobites of North America, p. 42. 1832. 
Calymene bufo. Hall. Geology N. Y., Part, iv, p. 201. 1843. 
Calyme^ie hufo, Owen. Geolog. Exploitation of a part of Iowa, Wis. and Ill., p. 74, pi. xii, fig. 1, 1844. 
Phacops hufo, Emmons. Manual of Geology, p. 138, fig. 124 (6). 1860. 
Phacops rana, Hall. Descrijitions New Species of Fossils, etc., p. ,'55. 1861. 
Phacops rana, Hall. Fifteenth Kept. N. Y. State Cab. Nat. Hist., p. 93. 1862. 
Phacops rana. Meek and Wortiien. Geol. Surv. Ill., vol. hi., p. 447, pi. xi, figs. la-e. 1868. 
Phacops rana, Nicholson. Palaeont. Province of Ontario, p. 123, figs. .6, 6a. 1873. 
Phacops rana. Hall. Illustrations of Devonian Fossils, pi. vii, figs. 1-11 ; viii, figs. 1-17. 1876. 
Phacops rana, Whiteield. Geology of Wisconsin, vol. iv, p. 339, pi. xxvi, figs. 17-19. 1882. 
Compare Phacops ra7ia, Walcott. Palieont. Eureka District: Monog. U.S. Geol. Surv., vol. viii, p. 207. 1884. 
General Form and Proportions. Outline elongate sub-oval; greatest width 
(measured at the posterior margin of the cephalon) to axial length as I to 2. 
The cephalon, thorax and pygidium are to one another in length as 1.5 to 2 
to 1. Thoracic margins straight, sub-parallel, gently converging posteriorly, 
connecting the curves of the cephalon and pygidium, which are approxi¬ 
mately arcs of large and small circles respectively, the former with its center 
upon the occipital ring, the latter central upon the eighth thoracic segment. 
Cephalon arcuate, sub-semicircular, the regularity of the outline interrupted 
by the slight protrusion of the glabella and the genal extremities. Frontal 
margin obscure, concealed by the overhanging glabella; lateral edges faintly 
marginate and rounding to the obtuse genal angles; occipital margin nearly 
straight, bending backward on the axis. Occipital annulation strong, and 
equal in size to the segments of the thorax; occipital furrow narrow and 
becoming obsolete upon the cheeks. 
