[202]. Lake, Brit. Cambrian Tril. 1907, p. 45.
[203]. The British Carboniferous Proëtidae are described by H. Woodward, Monogr. Brit. Carb. Trilobites, Palaeont. Soc. 1883–84.
[204]. This can be maintained in the Crustacea by counting the seventh abdominal segment, which appears in Gnathophausia; but this is not universally regarded as a true segment. See also Nebalia (p. 111).
[205]. This and the following Sub-class correspond with Lankester’s Sub-class Euarachnida. The Delobranchiata have gills patent and exposed, and adapted for breathing oxygen dissolved in water. The Embolobranchiata have either the gill-books (now termed lung-books) sunk into their body, or the gill-books are wholly or partially replaced by tracheae. In either case the members of this Sub-class breathe atmospheric oxygen.
[206]. Woodward, “On some Points in the Structure of the Xiphosura, having reference to their relationship with the Eurypteridae,” Quart. J. Geol. Soc. xxiii., 1867, p. 28, and xxviii., 1871, p. 46. Milne Edwards, A., “Recherches sur l’anat. des Limules,” Ann. Sci. Nat. (5), xvii., 1873, Art. 4. Lankester, E. R., “Limulus an Arachnid,” Quart. J. Micr. Sci. xxi., 1881, p. 504. Kingsley, J. S., “The Embryology of Limulus,” Journ. Morph. vii. p. 35, and viii. p. 195, 1892–3. Kishinouye, “On the Development of Limulus longispina,” Journ. Coll. Sci. Japan, v., 1892, p. 53. Patten, W., and Redenbaugh, W. A., “Studies on Limulus,” Journ. Morph. xvi., 1900, pp. 1, 91.
[207]. Quart. J. Micr. Sci. xlviii., 1905, p. 165.
[208]. μηρός = a thigh.
[209]. This segment, though present in embryo Scorpions, has disappeared in the adults of those animals.
[210]. Quart. J. Micr. Sci. xlix., 1906, p. 469.
[211]. Zool. Anz. xiv., 1891, pp. 164, 173.