FE, R. Cowper Reed—Fossils from Dufton Shales. 217 
Dimensions. Length of head-shield : : 6 
Length of glabella + occipitalrme . 13 
Width of glabella at base . : > & 
Width of glabella at front end . etd 
Width of head-shield between eyes . 14 : 
Width of head-shield at base. _ zamilt 
cooocono:: 
OSTRACODA. 
Bryricuia (CERATOPSIS) DUFLONENSIS, sp. nov. Pl. XVII, Figs. 9-11la. 
Carapace semi-ellipitical, slightly oblique, rather elongate, widening 
a little posteriorly ; anterior end somewhat pointed ; posterior end wider 
and obliquely truncate above or rounded. Hinge-line straight, as long as 
carapace. Valves moderately convex, crossed by three swollen rounded 
lobes united below by sharp narrow sub-marginal ridge elevated into 
a thin rib on its crest running along middle of anterior lobe, then concen- 
trically with ventral margin, then up posterior lobe, bending obliquely 
forward to ascend to summit of the upstanding process of this lobe. 
Anterior lobe with a width about one-third the length of valve, 
narrowing slightly below, more or less swollen and rounded; first sulcus 
rather obliquely inclined backwards, traversing three-fourths the width 
of the shell; middle lobe narrow, prominent, straight, vertical, nearly 
reaching marginal furrow below; second sulcus straighter and more 
vertical than first sulcus ; accessory lobe represented by small node or 
tubercle almost isolated, situated about half-way down posterior lobe and 
separated from it by strong oblique sulcus, which is continued back- 
wards to about middle of posterior margin, expanding somewhat and 
dividing the posterior lobe into two unequal parts, of which the lower 
forms a small elongated elliptical lobe, obliquely directed upwards 
and forwards with the accessory lobe at its upper end; the upper 
portion of the posterior lobe is strongly elevated, rising nearly at 
right angles to valve, and projecting a little above hinge-line as 
a blunt sub-conical process with flattened posterior face, and with its 
lower edge sharpened by the continuation of the sub-marginal crest, and 
beaded or fimbriated. Border flattened, set at right angles to plane 
of valves, with median narrow raised rim ornamented with a row of 
closely placed small tubercles. Surface of valves smooth. 
mm, 
_ Dimensions. Length . : 2-75-3°0 
Width . eo 2.0 
ftemarks.—The relations. of this species are wide. The raised 
process on the posterior lobe closely resembles that of B. ( Cer.) 
oculifera, Hall,’ but the border of the valves is different. The crest 
on the lobes recalls the sub-genus Steusloffia,” and similar crests are 
present in Strepula,? but they have no genetic significance. . With 
B. ( Cer.) Chambersi, Miller,‘ our species agrees in the reduction or 
1 Jones, Q.J.G.S., 1890, vol. xlvi, p. 21, pl. iv, figs. 19, 20; Ulrich, Proc. 
U.S. Nat. Mus., 1908, vol. xxxv, p. 308, pl. xxxix, figs. 19, 20. 
® Ulrich, op. cit., p. 295, pl. xxxviii, figs. 1-5. 
° Jones, Ann. Mag. Nat. Hist., 1885, ser. v, vol. xvii, p. 403. 
“ Miller, Cincinnati Quart. Journ. Sci., 1874, vol. i, p. 234, fig: 27. 
