CERATIOCARIS ROBUSTA. 45 



A telson and two stylets, spread out. Dorsal aspect. Telson ridged. Some 

 bristle-bases visible along two rows, one on each side of the main ridge at the 

 broad upper part of the telson (not shown in the figure). Stylets flat, smooth, 

 with the usual rim and slight median ridge. 



PI. XI, fig. 8. Cambridge Mus. a/925. " Described by Salter, ' Ann. Mag. Nat. 

 Hist.,' ser. 3, vol. v, p. 158; figured by M'Coy, 'Brit. Pal. Foss.,' pi. i, E, fig. 7 c 

 (with 7d), as Pterygotus leptodactylus erroneously." 



This is a telson, with its head retaining some test, flattened and cracked, lying 

 sideways, and bearing some oblique marks, which are possibly remnants of a lattice 

 ornament. The lower part decomposed and rough, but evidently once ridged. 

 One stylet seen, flat and smooth, with delicate lateral rims, its test decom- 



The fossil occurs in brownish-grey shale ; finely micaceous, slightly calcareous 

 on the edge. From the Lower Ludlow Beds of Leintwardine. 



PI. XI, fig. 9. Cambridge Mus. a/926. Figured in the ' Brit. Pal. Foss.,' pi. i, 

 E, fig. Id. (See above, fig. 8.) In greenish-grey finely micaceous shale, cal- 

 careous on its edge. Leintwardine. A smooth, flat stylet, with slight lateral rims 

 (as in fig. 8). Outer edge rather convex. The upper end obliquely truncate, 

 probably natural, possibly by accident. The test is decomposed and mostly 

 broken away. 



PL XI, fig. 12. Brit. Mus. No. 58878. In thin, brown, hard shale; finely 

 micaceous. " Linburn, Muirkirk ; N.B. — C. W. P." 



Telson and two stylets outspread, showing their dorsal aspect. The telson-head 

 is flattened and cracked ; the lower part of the telson is somewhat convex, but 

 much corroded ; probably once ridged. Its extremity is shown by its impression 

 to have been very thin and sharp, and strongly, but delicately ridged. These 

 caudal spines are shorter than is usual with 0. robusta. 



PI. XI, fig. 13 a and b. Brit. Mus. No. 59620 (and its counterpart). 



In soft, light brown shale. Buckholm Beds, Gala Group ; Meigle Hills, 

 Galashiels. With Apt y chop sis. 



The telson and stylet are represented by a delicate impression, partly tinted 

 with iron-oxide. A small portion of the ultimate segment is represented by a 

 delicate smooth impression (not shown in the figure) above the telson, and of the 

 same width. The joint of telson to the ultimate segment, and of the stylet to the 

 telson are traceable. The telson is neatly ridged and shows two rows of puncta 

 for bristles (fig. 13 6); one row as shown in the figure, and another, less easily 

 seen, along the outer furrow. The stylet has a faint trace of having been slightly 

 ridged. 



PI. XI, fig. 14. British Museum, No. 39405. " Lower Ludlow ; Leintwardine. 

 Mr. Marston." 



