PLATE VI. 



(All the figures are of the natural size except fig. 4 b, magnified 3 diameters, and 

 fig. 4 c, 2 diameters.) 



Fig. 1. — Ceratiocaris Murchisoni (Agassiz). (Type specimen.) Broken caudal 

 spines, copied from ' Siluria,' 1867, pi. 19, fig. 1. (Specimen lost.) (Page 19.) 



Fig. 2. — The same. Imperfect head of a telson. Copied from ' Siluria,' 1867, 

 pi. 19, fig. 2. (Specimen lost.) (Page 19.) 



Fig. 3.— G. longa (?), T. R. J. & H. W. A stylet. Copied from ' Siluria,' 

 1867, pi. 19, fig. 3. (Specimen lost.) (Page 43.) 



Fig. 4. — 0. leptodactylus, M'Coy. (Type specimen, fig. 7 in ' Brit. Pal. Foss.,' 

 1855.) 4 a, a telson with piece of the ultimate segment ; 4b, portion of the telson, 

 with pits, enlarged 3 diameters ; 4 c, enforced contact of the telson and ultimate 

 segment, magnified 2 diameters. Cambridge Mus. (Page 15.) 



Fig. 5. — G. leptodactylus, M'Coy. (Original of fig. 7 a in ' Brit. Pal. Foss.,' 

 1855.) A telson, imperfect. Cambridge Mus. (Page 15.) 



Fig. 6. — The same. Part of an ultimate segment and of a telson (?). Mus. 

 Pract. Geol. (Page 15.) 



Fig. 7. — The same. Three caudal spines, not quite perfect. Mus. Pract. 

 Geol. (Page 15.) 



Fig. 8. — The same. Caudal spines, imperfect. Mus. Pract. Geol. (Page 16.) 



Fig. 9. — The same. Style and stylet. Mus. Pract. Geol. (Page 16.) 



Fig. 10. — G. valida, T. R. J. & H. W. Three caudal spines (not quite perfect), 

 with a fragment of the ultimate segment Copied from the 'Geol. Mag.,' vol. hi, 

 pi. 10, fig. 8. Dudley Mus. (Page 21.) 



Fig. 11. — The same. Portion of three caudal spines. Copied from the ' Geol. 

 Mag.,' vol. hi, pi. 10, fig. 9. Mus. Pract. Geol. (Page 21.) 



Fig. 12. — C. Bohemica, Barrande. Dorsal view of the head of a telson. 

 Copied from the ' Geol. Mag.,' vol. iii, pi. 10, fig. 10, for comparison. British 

 Mus. (Page 21.) 



