Palaeozoic Bi'valved Entomostraca. 323 



4. Entomis variostriaiay J. M. Clarke. 

 (PI. XL figs. 5-8.) 



Entomis i-ariostrinta, Clarke, Xeues Jahrb. f. Min. &c., 1884, vol. i. 

 p. 184, pi. iv. \vr. 3. 



Mr. J. M. Clarke, of Albany, New York, found this species 

 rather abundant in the Intumescens-ViiAk, belonging to the 

 lower part of the Upper Devonian, at Bicken, Westphalia. 

 The specimens he described in liis 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. 'J'hcsc carapaces arc 

 subglobular, or, rather, subovatc, 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 sliape 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; 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 striaj are numerous delicate, transverse, flexuous, and 

 branching lines, starting from the lower or underside of the 

 linear wrinkles or costulee, 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 XL 



Fig, 1. Entomis seyratostriata (Sandb.). a, hollow impression of left 

 valve, X 30 diam. ; b, ornament of the same, X 75 diam. From 

 N.N.W. of Whiteway Farm. 



Fiff.2. Ento7nis setratosti-iaia (Sandh.). a, convex cast of jight valve, 

 X 30 diam. ; b, ornament of the same, showing ridges and 

 pimples, X 75 diam. From N.N.W. of Whiteway Farm. 



Fiff. 3. Entomis Richteri, sp. no v. 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 vatiostriata, Clarke. Left valve, X 30 diam. 



