DITHYKOCARIS TESTUDINEA. 147 



bent forwards. Close to the posterior angles, over a limited area, these lines are 

 lost among small tubercles (visible in a photograph). The two moieties of the 

 carapace together present an elegant symmetrical pattern. In each valve the 

 lines converge at the antero-dorsal region. 



The abdominal segments exposed in this specimen are much obscured by pres- 

 sure; and have been so squeezed as, at first sight, to look like numerous (eight or 

 more) very short rings (such as those in Apus and Lepidioms) ; and are crushed 

 in along the middle line. This false appeai^ance of many rings, however, is due 

 to the relative prominence of the transverse, sinuous, overlapping lines of growth 

 on the segments being emphasised by pressure. 



The style and stylets are stout, fluted, and have traces of granulation on the 

 riblets. They are of nearly equal length. They have had their position reversed, 

 showing their ventral and not their dorsal surface. 



Fig. 7 is from Dr. Scouler's original specimen, described by him in 1835. It 

 is in hard black earthy limestone, from the Carboniferous Limestone series, 

 " about a mile ^ to the east of Paisley " (' Records, &c.,' p. 136). 



It was also described and figured by Woodward and Etheridge in 1873, and 

 has been lent to us by the Trustees of the Andersonian Museum (Technical 

 College) at Glasgow. 



PL XIX, fig. 7; and PL XXII, fig. 3 (front end magnified). Brit. Mus. 

 No. 59541, No. 15. 



Size. — Length of carapace 27 mm. ; breadth of carapace 20 mm. 



Characters. — Carapace, with its two moieties, or pair of valves, flattened out, 

 but in natural apposition at their dorsal margins. Damaged in the middle ; it is 

 broadly oval in outline. Indented in front by a small notch at the junction of the 

 valves; its edges are there fringed with minute spines (PL XXII, fig. 3). Pos- 

 teriorly each valve has a strong spine, continuous with the ventral border ; and 

 curving in between them, with two gently convex curves, the one valve meets the 

 other in a central notch. There is a faint trace of the marginal fringe on each 

 valve. The surface exhibits the peculiar oblique lineation of the species ; also 

 some gastric tubercles, and traces of the two mesolateral ridges. 



In black shale, slightly calcareous. Probably from East Kilbride. 



PL XIX, fig. 8; PL XXXI, fig. 1 (ornament). Brit. Mus. No. 1.109, No. 21. 

 Size. — Length of valve about 50 mm. ; breadth of valve about 23 mm. 

 Characters. — Two valves, showing their insides, displaced, but lying back to 

 back ; neither of them perfect. A part of the anterior notch is traceable. The 



1 At a place now called "Inkermann," where Mr. E. Dunlop has lately most obligiugly sought 

 for further indications of these fossils, but without success. 



