DEVONIAN FAUNAS. 321 
HOMALONOTUS VANUXEMI Hall. 
Plate XXXIX., Figs. 7-8. 
See, also, p. 338, pl. XLIV. 
A single specimen of the pygidium of this trilobite has been recog- 
nized in the Becraft limestone. It is of about average size, having a 
length of 38 mm., and differs in no respect from the later representa- 
tives of the species. So far as has been observed in New Jersey, this 
is the earliest occurrence of the species, it being most abundantly 
represented in the limestone at the base of the Oriskany series. 
PHACOPS LOGANI Hall. 
Plate XL., Figs. 3-4. 
1859. Phacops logani Hall, Pal. N. Y., vol. III., p. 353, pl. 73, figs. 
15-25. 
Description.—General form of the entire trilobite longtitudinally 
elliptical. Head subcrescentiform, somewhat pointed in front, the 
genal angles rounded. Glabella large, subpentagonal in outline, broader | 
than long, prominent and protuberant in front, bounded laterally by 
deep and narrow dorsal furrows, which converge posteriorly; upper 
surface convex. The two anterior pairs of lateral furrows very faint, 
extending obliquely forward from the margins of the glabella; the 
third pair strongly defined and continuing across the posterior portion 
of the glabella, cutting off a well-defined posterior segment, at each 
extremity of which is a prominent, subovate tubercle. Cheeks com- 
paratively small, not extending forward beyond about the mdidle of 
the glabella, but more conspicuous posteriorly, where they are bordered 
by a smooth, convex margin. LHyes rather large, their summits less 
elevated than the glabella, containing seventeen vertical rows of lenses, 
full-grown individuals having about one hundred lenses altogether in 
each eye. Occipital furrow strongly defined on the axis, produced 
upon the cheeks, terminating within the marginal border. Occipital 
segment convex, rather broad and prominent. Surface of the glabella 
pustulose, and on perfectly-preserved specimens the occipital segment 
bears one median tubercle, with several smaller ones on each side. 
21 
