DESCRIPTION OF GENERA AND SPECIES. I4I 
associated pygidium has a proportionately shorter axial lobe and its sides curve 
outward instead of inward. 
Formation and Locality.—Middle Cambrian: (85r) Fu-chéu series, limestones 
near the base of the series just above the white quartzite [see Blackwelder, 1907), 
p- 92, for general section giving stratigraphic relations], collected in a low bluff on 
the shore of Tschang-hsing-tau Island, east of Niang-niang-kung, Liau-tung, 
Manchuria, China. 
Collected by J. P. Iddings and Li San. 
Crepicephalus damia Walcott. 
Plate 13, Figures 14, 14a—-b. 
Crepicephalus damia WaA.corT, 1905, Proc. U.S. Nat. Mus., vol. xxrx, p.92. (Described and discussed 
as a new species essentially as below.) 
Cephalon semicircular in outline, with the postero-lateral angles terminating 
in round, somewhat incurved spines. Glabella moderately convex, with the sides 
narrowing slightly toward the front, which is broadly rounded; length a little 
greater than its width at the occipital furrow; marked by three pairs of furrows; 
the posterior pair extends obliquely inward and backward so as almost to separate 
a triangularly shaped lobe; second pair rather faint, extending directly inward a 
distance of about one-third the width of the glabella, and then curving slightly 
backward; anterior pair very faint; occipital furrow rather broad and strongly 
defined; occipital ring narrow at the ends, rounded, and rather strong in the central 
portions; dorsal furrow clearly defined on the sides, but obscure in front of the 
glabella. 
Fixed cheeks about one-half the width of the glabella; posteriorly they slope 
downward into postero-lateral limbs that are about twice as long as the width of 
the fixed cheeks; toward the front the fixed cheeks slope abruptly downward and 
merge into the frontal limb; palpebral ridges low and broad, merging into the strong 
palpebral lobe; postero-lateral limbs grooved near the posterior margin by a strong 
furrow; frontal limb short, almost flat, and sloping abruptly from the front of 
the glabella down to the strong, nearly flat, frontal rim; the body of the associated 
free cheek is subquadrilateral in outline, marginal borders strong, clearly defined, 
and produced behind a strong, slightly curved, rounded spine. 
Thorax unknown. 
The associated pygidium is quadrilateral in outline, exclusive of the strong, 
slightly diverging postero-lateral spines, which are a little longer than the length 
of the pygidium; sides of the pygidium subparallel or slightly diverging toward 
the base of the spine; posterior margin nearly transverse; axial lobe prominent, 
convex, and reaching nearly to the posterior margin; the sides converge slightly 
toward the bluntly pointed posterior end; divided by three transverse furrows 
into three segments and a strong terminal portion, which is marked at the point 
where the axis slopes abruptly downward by a small node on each side; the pleural 
lobes are limited to a rather large anterior lobe, and an obscure secondary lobe, 
which appears to merge backward into the postero-lateral spine. 
Surface apparently smooth under a strong lens; a few scattered puncte occur 
on the glabella. 
The largest cephalon has a length of 10 mm., with a width of 12 mm. at the 
palpebral lobes. 
This species differs from Crepicephalus iowensis Owen [1852, p. 573], to which 
it appears to be most nearly related, by the form of the frontal limb and rim of the 
glabella and other details; the pygidium is not so broad, and it also differs in outline. 
