CLASs II GKAPTOLITOIDEA 125 



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Appendix to the Hydromedusae. 



Olass or Subclass. GRAPTOLITOIDEA Lapworth.i 



{Rhabdophom Allman.) 



Under the term of Graptolitoidea are included organisms which have been 

 considered by various authors as plant remains, horny sponges, Pennatulidae, 

 Cephalopods and Bryozoans. Portlock, in 1843, first pointed out their 

 analogy with the Sertularians and Plumularians ; and his inferences as to 

 their genetic relationship were afterwards confirmed by the painstaking 

 researches of Allman, Hall, Hopkinson, Lapworth, Nicholson, and others. 

 More recently, however, their kinship has been denied by Neumayr and 

 Wiman, who, on account of the bilateral symmetry of the sicula and thecae, 

 claim that Graptolites cannot be included within any of the now existing 

 classes of organisms. 



Graptolites are generally found in an imperfect state of preservation, lying 

 flattened in the same plane upon the slaty laminae in which they are embedded, 

 and associated in large numbers. More rarely they occur in limestone, when 

 the internal cavities are filled with calcareous matter, and the original form 

 accurately preserved. Such specimens have been successfully etched out and 

 investigated under the microscope by Holm and Wiman. 



The general skeletal tissue (periderm) was obviously flexible, and composed of 



^ Literature : Hall, J., Palaeontology of New York, vols. i., iii., 1847, 1859. — Graptolites of 

 the Quebec Group. Cauad. Organic Remains, dec. ii. Geol. Surv. Cauad., 1865. — lutroduction to 

 the study of Graptolites. 20th Ann. Rept. N.Y. State Gab. Nat. Hist., 1868.— Barrande, J., Grapto- 

 lites de Boheme. Prague, 1850. — 8uess E., über böhmische Graptolithen. Haidinger's Naturw. 

 Abhandl., 1851, vol. iv. — Scharenherg, PF., Ueber Graptolithen. Breslau, 1851. — Geinitz, H. B., 

 Die Versteinerungen der Grauwackenformation in Sachsen, Leipzic, 1852. — Die Graptolithen des 

 mineral. Museums in Dresden, 1890. — Richter, R., Thüringische Graptolithen. Zeitschr. Deutsch. 

 Geol, Ges., vols. v., xviii., xxiii., 1853, '66, 71. — Nicholson, II. A., Monograph of the British 

 Graptolitidae, 1872. — Lapworth, C, Notes on the British Graptolites. Geol. Mag., vols. x., xiii., 

 1873, '76. Also various articles in Quart. Journ. Geol. Soc, 1875, '78, '81, and Ann. Mag. Nat. 

 Hist., 1879, '80.— On the Graptolites of County Down. Ann. Rep. Belfast Nat. Field Club, 1877, 

 vol. i., pt, iv, — Tullberg, S. A,, On Species of Didymograptus. Geol. För. Stockholm Förh,, 1880, 

 vol. v. — Spencer, J. W., Graptolites of the Upper Silurian System. Bull. Mus. Univ. Missouri, 1884. 

 — Tornquist, S. L., Observations on Graptolites. Acta Univ. Lund, 1890-92, vols. xxvii.-xxix. — 

 Holm, G., Skandinaviens Gi'aptoliter. Svensk, Vetensk. Akad. Förh., 1881, vol. xxxviii. — Gotland's 

 Graptoliter. Bihang Svensk. Vetensk, Akad. Handl. 1890, vol. xvi. — Barrois, C, Memoire sur la 

 distribution des graj)tolites en France. Annales Soc. Geol. Nord, 1892, vol. xx.— Wiman, C, Über 

 Monograptus und Diplograptidae. Bull. Geol. Inst. Upsala, 1893, vol. i. (English translatiou in 

 Journ. Geol., 1893, vol. ii.). — Tornquist, S. L., Observations on the Structure of some Diprionidae. 

 Fisiogr. Sällsk. Handl., 1893, '97, vols. iv., viii. — Researches into the Graptolites of the Scanian and 

 Vestrogothian Phyllo-Tetragraptus Beds. Lunds Univ. Arsskrift, 1901, vol. xxvii. — Ferner, J., 

 liltudes sur les graptolites de Boheme. Prague, 1894-99. — Holm, G., Om Didymograptus, Tetra- 

 graptus och Phyllograptus. Geol. För. Förh., 1895, vol. xvii. No. 164. — Ruedemann, R., Synopsis of 

 the Mode of Growth and Development of the Genus Diplograptus. Amer. Journ. Sei. (3), 1895, vol. 

 xlix. ; Also in Ann. Rept. N.Y. State Geol. 1894, and Amer. Nat., 1897, vol. xxxii. — Graptolites of 

 New York, N.Y. State Museum. Memoirs vii. 1904, and xi., 1908. — Gurley, R. R., North American 

 Graptolites. Journ. Geol., 1896, vol. iv. — Wiman, C, Über die Graptolithen. Bull. Geol. Inst. 

 Up.sala, 1895, vol. ii. ; also Nat. Sei., 1896, vol. ix., and Bull. Geol. Inst. Upsala, 1897, No. 6. 1900, 

 No. 10. — EUes, G. L., and Wood, E. M. R., Monograph of British Graptolites, ed. by C. 

 Lapworth. Palaeontogr. Soc, 1901 to date. — Hall,T. S., Note on the Distribution of the Graptolitliidae 

 in the Rocks of Castlemaine. Rept. Austral. A.ssn. Adv. Sei., 1894 ; also Proc. Roy. Soc. Victoria 

 1892, '97, '98, '99 ; Geol. Mag,, 1899, vol. vi.—Roemer, F., and Frech, F., Lethaea Palaeozoica, 1897, 

 vol. i. — Bassler, R. S., Dendroid Graptolites of the Niagarau Dolomites at Hamilton, Ontario. 

 Bull. Smithson. Inst., No. 65, 1909. — Westergard, A. H., Studier öfver Dictyograptus.skiffern. Med. 

 fr. Lunds Geol. Fält Klub. Ser. B, No. 4, 1909. 



