Palaeozoic Bivalved Entomostraca. 
323 
4. Entomis variostriata , J. M. Clarke. 
(Pl. XI. figs. 5-8.) 
Entomis variostriata , Clarke, Neues Jalirb. f. Min. &c., 1884, vol. i. 
p. 184, pl. iv. fig. 3. 
Mr. J. M. Clarke, of Albany, New York, found this species 
rather abundant in the Intumescens- Kalk, belonging to the 
lower part of the Upper Devonian, at Bicken, Westphalia. 
The specimens he described in his paper when he was in 
Germany were from 2 to 2^ millim. long ; but the only 
examples that he could lately send for examination and 
figuring are smaller, though plentifully distributed in two 
little pieces of the rock from Bicken. These carapaces are 
subglobular, or, rather, subovate, with a high convexity in 
the middle (1*8 millim. in fig. 8) ; glossy black and of many 
sizes, scattered through a dull black limestone, and leaving 
glossy impressions. They vary from 1*6 x 1*3 millim., 1’4 x 
•76 millim., 1*2 x *9 millim., to # 6 x ‘4 millim., and smaller. 
The sulcus, as noticed also in Mr. Clarke’s description, loses 
its simple furrow-like shape in some cases by having its sides 
unequally raised or by being represented only by a central 
pit ; in the small (probably young) state, fig. 7, the sulcus is 
not well developed j and the other conditions may also belong to 
stages of growth. The ornament is essentially a concentric 
series of thin, raised, interrupted lines, like those of Entomis 
gyrata (see figs. 4 & 5) . In fig. 8 a they are quite concentric 
to the central pit, but with a somewhat angular or lozenge- 
like contour ; in fig. 6 a ) however, they are curved at one end 
of the valve and longitudinal at the other. Between these 
raised striae are numerous delicate, transverse, flexuous, and 
branching lines, starting from the lower or underside of the 
linear wrinkles or costulae, and dying out before they quite 
cross the interspaces (fig. 6 h ) . The variability of the 
ornament has been very appropriately recognized as charac- 
teristic of this German species. 
EXPLANATION OF PLATE XI. 
Fig. 1. Entomis serratostriata (Sandb.). a y hollow impression of left 
valve, x 30 diam. ; 6, ornament of the same, X 75 diam. From 
N.N.W. of Whiteway Farm. 
Fig. 2. Entomis serratostriata (Sandb.). a, convex cast of 'right valve, 
X 30 diam. ; b, ornament of the same, showing ridges and 
pimples, X 75 diam. From N.N.W. of Whiteway Farm. 
Fig. 3. Entomis Richteri , sp. nov. Left valve, somewhat crushed, X 30 
diam. From Whiteway Farm. 
Fig. 4. Entomis gyrata (Richter), variety. Left valve, imperfect, X 30 
diam. From the Castle-Dyke Quarry. 
Fig . 5. Entomis variostriata , Clarke. Left valve, X 30 diam. 
