DESCRIPTION OF GENERA AND SPECIES. 135 
Of the species from China of this subgenus, P. (E.) theano (Walcott) [plate 13, 
fig. 2], P. (E.) bromus (Walcott) [fig. 3], and P. (E.) eriopia (Walcott) [fig. 4] have 
the posterior elongate palpebral lobe. In P. (Z.) mantoensis (Walcott) [fig.1] and 
P. (E.) constricta (Walcott) [fig. 5] the palpebral lobe is much like that of Ptycho- 
paria in its position. 
Stratigraphic Range—Ptychoparia (Emmrichella) mantoensis and P. (E.) con- 
stricta occur at the summit of the Lower Cambrian; P. (E.) eriopia and P. (E.) 
theano at the base of the Ch’ang-hia formation of the Middle Cambrian; and P. 
(E.) bromus at about the same horizon in the Kiu-lung formation. 
Ptychoparia (Emmrichella) bromus (Walcott). 
Plate 13, Figure 3. 
Ptychoparia ? bromus WaLcort, 1905, Proc. U. S. Nat. Mus., vol. xxrx, p. 76. (Described as a new 
species essentially as below.) 
This species is represented by the central portions of the cephalon, exclusive 
of the free cheeks. Glabella moderately convex, truncato-conical, rounded in front, 
and apparently without furrows; occipital furrow transverse and clearly defined; 
occipital ring strong and moderately convex; dorsal furrow broad and shallow. 
Fixed cheeks nearly as wide as the glabella opposite the palpebral lobe; they 
rise slightly from the dorsal furrow to the palpebral lobe, and slope gently back- 
ward to the postero-lateral limb and forward to the frontal limb; palpebral lobe 
narrow, about one-third the length of the cephalon; palpebral ridge rounded and 
faintly defined; frontal limb of medium width, slightly convex, and sloping gently 
down to a rounded furrow that separates it from the flattened frontal rim, which is 
about one-half as wide as the frontal limb. 
The surface is slightly roughened by minute granulations, as seen with the 
aid of a strong lens. 
The largest specimen of the cephalon in the collection has a length of 7 mm. 
This species is characterized by the rounded, smooth appearance of the glabella, 
fixed cheeks, dorsal furrow, and frontal limb. 
Formation and Locality——Middle Cambrian: (C6) Thin, platy limestone in 
the upper shale member of the Kiu-lung group [Blackwelder, 1907a, pp. 37 and 41 
(second list of fossils), and fig. 10 (bed 12), p. 38], 2.5 miles (4 km.) southwest of 
Yen-chuang, Sin-t’ai district, Shan-tung, China. 
Collected by Eliot Blackwelder. 
Ptychoparia (Emmrichella) constricta (Walcott). 
Plate 13, Figures 5, 5a. 
Ptychoparia constricta WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxrx, p. 77. (Described as a new 
species. ) 
The convex central portions of the cephalon, exclusive of the free cheeks, are 
subquadrilateral in outline. Glabella subcylindrical, narrowing slightly toward the 
front, with only faint indications of glabellar furrows; occipital furrow narrow, 
clearly defined, but shallow; occipital ring strong, narrow at the sides and broad at 
the center. 
Fixed cheeks about as broad as the glabella; palpebral ridges strong and merg- 
ing into the rather long palpebral lobes; frontal limb well defined by the palpebral 
ridges and narrow, slightly flattened frontal rim. 
Surface slightly roughened by minute, irregular, raised lines. 
Formation and Locality—WLower Cambrian: (C3) Lower part of the Man-t’o 
shale formation [Blackwelder, 1907a, p. 28 (list of fossils at bottom of page), and 
