136 



BRITISH PALEOZOIC PHYLLOCARIDA. 



II. DESCRIPTION OF THE SPECIES. 



1. Dithyrocaris glabra, Woodward and Etheridge, 1873. Plate XVIII, figs. 1, 2 ; 



Plate XIX, figs. 1—4 ; Plate 

 XXIII, fig. 11 ; Plate XXV, 

 figs. 1, 2. 



Dithteocaeis glabra, H. Woodward and B. Etheridge, ,/««., '1873. Mem. Geol. 



Survey Scotland, Ex plan. Sheet 23, 

 Appendix, p. 99. 



— — H. Woodward and B. Etheridge, jun., 1874. Geol. Mag., 



dec. 2, vol. i, p. 108, pi. v, figs. 4 and 5 ; Keport 

 Brit. Assoc, for 1873 (1874). Sect , p. 92. 



— — J. Armstrong, 1876. Catal. W.-Scot. Fossils, p. 45. 



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



— — Bigsby, 1878. Thesaur. Dev.-Carb., p. 249 



— — J. Coutts, 1884-5. Trans. Geol. Soc. Glasgow, vol. vii, 



pp. 200 and 327. 



— E., W., and J., 1887. Eep. Brit. Assoc, for 1886, p. 64. 



— Etheridge, 1888. Foss. Brit., vol. i, Palaeoz., p. 238. 



Size. — The following are the measurements of the two half-carapaces (PI. 

 XVIII, figs. 1 and 2) as given in the ' Geol. Magazine.' 1874, p. 109, for pi. v, 

 figs. 4 and 5 : 



Greatest breadth 

 Greatest length 

 Length along the dorsal line 

 Breadth of anterior notch 

 Depth of anterior notch 

 Breadth of posterior notch 

 Depth of posterior notch 



Large half-carapace 

 (fig. 4). 



Smaller lialf-carapace 



(fig. 5). 



25 



mm. 



22 



mm. 



62 



55 



55 



55 



40 



55 



30 



5} 



10 



55 



12 



33 



7 



55 



10 



35 



23 



35 



20 



35 



15 



55 



15 



55 



Specific Characters. — Valves (or moieties of carapace) elliptical ; smooth except 

 for a granulated antero-dorsal area, the granules sometimes extending over the 

 dorsal area. Dorsal junction of the valves overridden by a rugose ridge, like a 

 closely set row of ridge-tiles (PI. XXV, figs. 1 and 2). Sometimes there is a faint 

 indication of a mesolateral ridge (PI. XIX, figs. 1 and 3). 



Abdominal segments exposed, few ; trifid appendage of strong style and 

 stylets of nearly equal length (PL XIX, fig. 3; and PI. XXIII, fig. 11). 



1 Tlie joint authorship is mentioned at p. 98. 



