38 BRITISH PALiEOZOIC PHYLLOCARIDA. 



PI. XII, fig. 1. British Museum, No. 58669. In the black Upper Silurian 

 shale of Lesmahago, Lanarkshire (Slimon Collection). 



Two valves, delicately striate ; shifted and squeezed ; the right valve upper- 

 most. "With five body-segments at the anterior, instead of the posterior end. 

 Style and stylets broken and displaced. 



B. M. 41900 (PI. XI, fig. 6) and 41901 (counterpart), Lesmahago. Three 

 abdominal segments, lattice-marked and obliquely striate, and an ultimate segment 

 with both oblique and straight striae, probably due to two layers of the test. 

 Telson, 30 mm. long ; and two ensiform stylets, each about 13 mm. long. 

 Pressed flat in slightly calcareous black shale. 



Also Oxford Mus. H. (PI. XI, figs. 4 a, 4 &) with four segments, style 30 mm., 

 and stylet 15 mm., pressed sideways, in olive-grey shale ; Ludlow (?). 



It is possible that G. papilio may have been the male, and G. stygia the female 

 of the one species. 



11. Ceratiocakis stygia, Salter, 1860. PI. X, figs. 7 a and b; PI. XI, figs. 1, 3, 



and 7 ; PI. XII, figs. 2 a, 2 b. 



1859. Cebatiocaeis, Salter. In Murchison's Siluria, 2nd (3rd) ed., p. 262, 



woodcut fig. 2. 



1860. — STYGius, Salter. Ann. Mag. Nat. Hist., ser. 3, vol. v, 



p. 154, woodcut figs. 2, 3 (fig. 1 is 

 C. papilio). 

 1865. — — R.Sf E. Catal. Foss. M. P. G., p. 79. 



1865. — PAPILIO, Salter and Woodward. Cat. and Chart Foss. 



Crust., p. 17, fig. 5. 

 1867. — STYGIUS, Salter. In Siluria, 3rd (4th) ed., p. 2.?6, woodcut 



fig. 2, and p. 517. 

 1873. — — — Cat. Camb. and Sil. Woodw. Foss., p. 178. 



1873. — — B. Etheridgejun. Mem. Geol. Surv. Scotl. Expl. 



Map 23, pp. 55, 56. 

 1876. — PAPILIO, F. Eoem. Leth. geogu., Th. i, Leth. Pal., pi. 19, 



fig. 4. 



1876. — STTGius, Armstrong and others. Cat. W.-Scot. Fossils, 



p. 24. 



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



1878. — — Huxley, Newton, and Etheridge. Cat. Camb. Sil. 



Fossils, p. 142. 



1885. — — T. R. J. Sf H. W. Third Eeport Pal. Phyll., 



p. 343 ; Geol. Mag., 1885, p. 394, pi. 10, figs. 

 2 a, b, c. 



1886. — — T. li. J. ^ H. W. Fourth Eeport, p. 231 ; Geol. 



Mag., 1886, p. 458. 



