ON THE FOSSIL PHTLLOPODA OF THE PALEOZOIC BOOKS. 229 



Fourth Report of the Committee, consisting of Mr. R. Etheridgie, 

 Dr. H. WooDWAED, and Professor T. Rdpert Jones {Secretm-y), 

 on the Fossil Phyllopoda of the Palaeozoic Rocks. 



Ge/nera ami Species. 



Ceratiocaris leptodactylus (M'Coy). 



C. Murchisoni (Agass.)- 



C. gigas, Salter. , 



C. valida, nov. 

 o. C. attenuata, nov. [? tyrannus, Salt.] 

 1(5. C. canaliculata, nov. 



C. Halliana, nov. 



C. Pardoeana, La Touche. 



C ludensis, H. W. 



C. robusta, Salter, C. lata, angusta, 

 and minuta, now. 

 H. C. papilio and C. stygla, Salter. 

 ] 3. C. laxa, nov. 



C. Salteriana, J. & W. 



C. cassia, Salter, C. cassioides, nov. 



C. compta, nov. 



C. inornata, M'Coy. 



C. Kuthveniana, nov. 



1. 



7. 



S. 



1). 



10. 



13. 

 14. 

 15. 

 16. 

 17. 



Genera and Species. 



18. C. oretonensis and C. truncata, H. W. 



19. C. solenoides (M'Coy), and C. gobii- 



formis, J. & W. 



20. Emmelezoe elliptica M'Coy ; E. tenui- 



striata, nov. ; E. cras.si striata, 

 nov. ; E. Maccoyiana, nov. 



21. Xiphocaris ensis (Salter). 



22. Physocaris vesica, Salter. 



23. C. ? spp. 



24. C. ? longicanda (D. Sharpe). 



25. Ptychocaris simplex and Pt. parvnla, 



Ov4k. 



26. Cryptozoe problematica, Packard. 



27. Geological localities of Mr. J. M. 



Clarke's fossil Phyllopods. 



28. List of British Palifiozoic Phyllo- 



carida described in the Third 

 and Fourth Reports. 



Introduction. 



Since the publication of the Third Report on Palaeozoic Phyllopoda 

 ('Brit. Assoc. Report' for 1885) vee have examined many addi- 

 tional specimens in the Museums of the Edinburgh and Glasgow Uni- 

 versities, and in the Braidwood Museum belonging to Dr. J. R. S. Hunter, 

 of Braidwood, near Glasgow. Mr. James Thomson, F.G.S., has given 

 us a quantity of nodules, containing remains of Ceratiocaris, from the 

 Lesniahago district ; and other friends have lent us several interesting 

 specimens. 



We have also again critically examined the fossils enumerated, under 

 ' Ceratiocaris,' in the ' Third Report,' and, having had numerous finished 

 drawings carefully made for illustration of a forthcoming monograph for 

 the Palseontographical Society, we have been able to compare them more 

 perfectly and with more precise results. 



Thus we find that — 



1. Ceratiocaris leptodactylus (M'Coy), see ' Third Rep.' pp. 11-14, as 

 known by its caudal appendages (Cambr. Mus. a/923, a/924, and a few 

 others), is distinct from G. Murchisoni, M'Coy, both as to size and 

 proportions. "We have traced two rows of pits (bases of prickles) on 

 «/924, as exposed. Some similar caudal appendages, M.P.G. \^, occur 

 in the Lower Wenlock rock of Helm Knot, Dent, Yorkshire. 



2. G. Murchisoni (Agass.), founded on some specimens figured in 

 ^ Sil. Syst.' and ' Siluria,' but unfortunately lost (' Third Rep.' p. 11, &c.), 

 is represented by several analogous fossils, such as Oxford Mus. B and C ; 

 Ludlow Mus. C ; M.P.G. f | and §f . We find only one row of pits on the 

 ■styles, as exposed. We have been unable to determine its carapace ; but 

 ■a fragment lying in the same slab with |f may belong to it. The cara- 

 paces formerly assigned to G. leptodactylus and C. Murchisoni (' Third 

 Rep.' pp. 12, 15) are now regarded as belonging to distinct species. 



3. The caudal appendages of G. Murchisoni have a slight curvature ; 

 there are others much like them, but straight, and associated with a 

 iarge ultimate segment, much broader than that in M.P.G. |f. (For 



