DITHYROCARIS TESTUDINEA. 145 



PI. XIX, fig. 5. Mus. Sci. and Art Edin., Coutts, 1887, ff, No. 9. 



Size. — Length of valve, imperfect, 48 mm. ; breadth of valve about 25 mm. 



Characters. — This is a right valve, imperfect at its posterior end ; though much 

 depressed at its edges, it retains some convexity. The surface is tuberculate on 

 the antero-dorsal and the dorsal region ; but otherwise smooth and shining. 



The sigmoidal cephalic ridge is nearer to the dorsal edge than usual, probably 

 owing to some displacements in the antero-dorsal region by pressure. The dorsal 

 edge is nearly straight, but irregularly broken. The ventral edge has the narrow 

 fringe or neatly corded rim as usual for a great part of its extent. 



The mesolateral ridge is thin, but very distinct ; there are some low, irregular 

 elevations at its front end. 



In black shale, slightly calcareous, from East Kilbride. 



4. Dithyrocaris tkstudinea, Scolder, 1835. Plate XIX, figs. 7 — 9 ; Plate XXI, figs. 



1—6 ; Plate XXII, fig. 3 ; Plate XXIII, figs. 7 (?), 8 ; 

 Plate XXIV, fig. 7 ; Plate XXVII, figs. 3 a, b ; 

 Plate XXVIII, figs. 1 a, b, 2, 3 a, &, 4, 5 a—c ; Plate 

 XXIX, figs. 10—14 ; Plate XXXI, figs. 1—3, 4. 



Aegas testudineus, Scolder, 1835. Becords of General Science (Thomson's), 



vol. i, pp.137, 141, fig. 3. 

 Dithyeocabis testudineus, Morris, 1854. Catal. Brit. Foss., edit. 2, p. 107. 



— — Salter and Woodward, 1865. Chart Boss. Crustacea, 



p. 17, fig. 11. 

 _ _ ? (teeth), /. Young, 1868. Trans. Geol. Soc. Glasgow, 



vol. i, p. 58. 



— — J. Armstrong, 1871. Trans. Soc. Geol. Glasgow, 



vol. iii, Appendix, p. 30 ; and 1876, Catal. W. 

 Scot. Fossils, p. 45. 

 _ — R. Woodward and B. Ether idge, jun., 1873. Mem. 



Geol. Surv. Scotl., Bxpl. Sheet 23, 

 Appendix, p. 98 ; and Geol. Mag., 

 vol. x, p. 482, pi. xvi, fig. 1. 



J. B. S. Hunter, 1875. Palaeont. Carb. Strata W. 



Scotland, part ii, p. 65. 



— testudikea, H. Woodward, 1877. Catal. Brit. Foss. Crust., p. 73. 

 _ _ Birjsby, 1878. Thesaur. Dev.-Carb., p. 249. 



Non Dithyeocabis testudinetjs, B. Etheridge, jun., 1879. Quart. Journ. Geol. Soc, 



vol. xxxv, p. 465, pi. xxiii, fig. 1. 

 Abgus testudineus, Packard, 1883. North-American Phyllop., p. 452. 

 Dithyeocabis testudineus, J. Coutts, 1884-5. Trans. Geol. Soc. Glasgow, 



vol. vii, pp. 197 and 327. 

 _ — E., W., and J., 1887. Eep. Brit. Assoc, for 1886 



(18S7), p. 63. 



