108 Woodward and Etherldge — On Dithyrocaris. 



Locality. — Kirktonholm Cement Works, in shale above the Calder- 

 wood Cement Stone (L. Limestone Group). Cabinet of Mr. A. 

 Paton, E. Kilbride. 



4. Dithyrocaris granulata, Woodw. and E. (PI. V. Figs. 2 and 

 3), Mems. Geol. Survey, Expl. Sheet 23, Scotland, 1873, p. 99. 



This species is represented by two half-shields or valves, — which 

 have apparently separated down the dorsal line, —the larger (Fig. 2) 

 measuring 40 mm. in its greatest length, and 18 mm. in its greatest 

 breadth; the smaller (Pig. 3) 31 mm. long, and 15 mm, broad. 



The outline of the shield is elliptical, with a broad but shallow 

 rounded notch at the anterior (rostral) end, and a deeper but broader 

 one at the posterior extremity. The angles of both are marked at 

 the anterior end by a short blunt spine, and at the posterior by a 

 more acute spine on each side. The breadth and depth of the 

 posterior notch are twice as great as that of the anterior one. 



The median or dorsal line is marked by the same characteristic 

 transverse scale-like markings, and the latero-posterior border by 

 parallel oblique raised lines ; a slightly raised line marks each valve 

 parallel to and midway between the dorsal line and the lateral 

 margin. The marginal or outer half of each valve is nearly (if not 

 quite) smooth; the inner half of each, nearest the dorsal line 

 (especially near the anterior notch), is finely granulated. 



The anterior part of each valve bears two minute rugose ridges ; 

 that nearest and parallel to th€ dorsal line 3 mm. long ; that most 

 anterior and furthest from the dorsal line 4 mm. long. These 

 valves are perfectly flat and free from relief, save the slightly raised 

 dorsal and median line, and the thickened lateral margin. 



Locality. — Kirktonholm Cement Works, and Glebe Quarry, E. 

 Kilbride, in shale above the Calderwood Cement Stone (L. Limestone 

 Group). Collected by Mr. J. Bennie; collection of the Geological 

 Survey of Scotland ; and in the cabinet of Mr. A. Paton, E. Kilbride. 



5. Dithyrocaris glabra, W. and E. (PI. Y. Figs. 4 and 5), Mems. 

 Geol. Survey, Expl. Sheet 23, Scotland, p. 99. 



Although not comparable in point of size with D. tricornis, 

 Scouler, or D. Colei, Portlock, this is the largest of the four new 

 species described in the present paper. 



It corresponds most nearly in the outline of the carapace (when 

 restored) with Z). granulata ; but the surface is quite smooth and desti- 

 tute of all ornamentation, save the maxillary ridges and some minute 

 granulation near the anterior notch ; whilst the latero-posterior 

 border is ornamented by oblique raised parallel lines. 



The species is represented by the half-shields of two individuals 

 of different sizes, one of which (Fig. 4) is compressed perfectly flat, 

 the other (Fig. 6) retains its normal tumid contour. 



The anterior margin of each valve is produced into a small short 

 spine ; the posterior margin into a more robust recurved one. 



The centre of the carapace is indented by a narrow sinuous notch 



