Cainozoic.—Zittel, K. Novara Exped. Geol. Theil., vol. I. Abth. II. 1864, pp. 34-55 (Pelec. and Gastr. New Zealand). McCoy, F. Prod., Pal. Vict., Dec. I. 1874; Dec. II. 1875; Dec. III. 1876; Dec. V. 1877; Dec. VI. 1879. Woods, J. E. T. Proc. R. Soc. Tas. (1875), 1876, pp. 13-26 (Table Cape Moll.). Idem, Proc. Linn. Soc. New South Wales, vol. III. 1879, pp. 222-240 (Muddy Creek Moll.). Idem, ibid., vol. IV. 1880, pp. 1-24. Hutton, F. W. Trans. New Zealand Inst. vol. IX. 1877, pp. 593-598. Ibid., vol. XVII. 1885, pp. 313-332 (New Zealand Pelec. and Gastr.). Idem, Proc. Linn. Soc. New South Wales, vol. I. 2nd ser. (1886), 1887, pp. 205-237, (distr. lists, Pareora and Oamaru). Idem, Macleay, Mem. Vol. Linn. Soc. New South Wales, 1893, pp. 35-92 (Pliocene Moll. New Zealand). Tate, R. Trans. R. Soc. S. Austr., vol. VII. 1886, pp. 96-158, and vol. IX., 1887, pp. 142-189 (Pelec.); ibid., pp. 190-194 (Scaphopoda); ibid., 194-196 (Pteropoda). Idem, ibid., vol. X. 1888, pp. 91-176; vol. XI. 1889, pp. 116-174; vol. XIII. 1890, pp. 185-235; and vol. XVII. 1893, pp. 316-345 (Gastr.). Idem, Journ. R. Soc., New South Wales, vol. XXVII. 1893, pp. 169-191. Idem, ibid., vol. XXXI. 1897, pp. 392-410 (Gastr. and Pelec.). Idem, Trans. Roy. Soc. S. Austr., vol. XXIII. 1899, pp. 260-277 (Revision of Moll.). Pritchard, G. B. Proc. Roy. Soc. Vic., vol. VII. 1895, pp. 225-231 (Pelec.). Idem, ibid., vol. VIII. 1896, pp. 79-141 (Moll. of T. Cape). Idem, ibid., vol. XI. pt. I. 1898, pp. 96-111 (Gastr.). Idem, ibid., vol. XIV. pt. I. 1901, pp. 22-31 (Pelec.). Idem, ibid., vol. XVI. pt. II. 1903, pp. 87-103 (Pelec.). Idem, ibid., vol. XVI. pt. I. 1903, pp. 83-91 (Pleurotomaria). Idem, ibid., vol. XVII. pt. I. 1904, pp. 320-337 (Gastr.) Idem, ibid., vol. XXVI. (N.S.) pt. I. 1913, pp. 192-201 (Volutes). Hall, T. S. Proc. R. Soc. Vict., vol. XVII. pt. II. 1905, pp. 391-393 (Chitons). Ashby, E. and Torr. W. G. Trans. R. Soc. S. Austr., vol. XXV. 1901, pp. 136-144 (Chitons). Thomson, J. A. Trans. New Zealand Inst., Vol. XL. 1908, pp. 102, 103 (N.Z. Moll.). Chapman, F. Proc. R. Soc. Vict. vol. XX. pt. II. 1908, pp. 218-220 (Chiton). Idem, ibid., vol. XXV. pt. I. 1912, pp. 186-192 (Gastr.).
[CHAPTER XI.]
FOSSIL TRILOBITES, CRUSTACEA AND INSECTS.
Arthropods and their Structure.—
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The above-named fossil groups are included by zoologists in the sub-kingdom Arthropoda (“joint-footed animals”). The Arthropods possess a body and limbs composed of a number of jointed segments covered externally with a hard, shelly material and separated by a softer, flexible skin. They have no internal skeleton, and therefore the only portion which can be preserved in the fossil state is the harder part of the outer covering. Under exceptional conditions of fossilisation, however, even frail insects such as ants, wasps and dragon-flies are sometimes found more or less wholly preserved and showing their original minute structure.
Subdivisions of Arthropoda.—
The principal representatives of the group of the Arthropods which are found as fossils include the Trilobites; various Crustacea proper, as Crabs, Lobsters, Shrimps, Pod-shrimps and Water-fleas; the Insects; and occasionally Spiders and Scorpions (Arachnida). The King-crabs and Eurypterids (as the extinct Pterygotus) form a separate sub-class, the Merostomata, which are placed by some authors in the group of Spiders and Scorpions: their remains date back to the time when the older Palaeozoic strata were deposited.