Published online by Cambridge University Press: 01 May 2009
THERE has been considerable uncertainty about the true characters of the species Illaenus bowmanni Salter, and many foreign palaeontologists have consequently found it difficult to institute a close comparison of it with other species and have suspected its composite nature. As Holm and Warburg have remarked, the species is badly characterized, and some important critical features, such as the shape of the caudal fascia, are ill-defined or not clearly described in the definitions or well represented in the figures. The poorness of the specimens is largely accountable for these omissions. A recent detailed investigation which the author has been enabled to make of the specimens used by Salter, Portlock, and McCoy in drawing up a definition of the species, together with the examination of many other specimens ascribed to it from the original and other localities, throws some useful light on the subject and helps to clear up some of the obscure points, but it also shows that most of the earlier and current synonymies and references which have been published from time to time are untrustworthy and inaccurate.
page 121 note 1 Salter, , Mem. Geol. Surv., ii, pt. i, 1848, 339, pl. viii, figs. 1, 2, 3; Mon. Brit. Trilob., pt. iv, 1867, 185, pl. xxviii, figs. 6–13, pl. xxx, fig. 6.Google Scholar
page 121 note 2 Holm, , Rev. Ostbalt. Silur. Trilob., Abt, iii, 1886, p. 153.Google Scholar
page 121 note 3 Warburg, , Trilob. Leptaena Limest., Bull. Geol. Instit. Upsala, xvii, 1925, 123, 132.Google Scholar
page 122 note 1 Salter, , Mem. Geol. Surv., ii, pt.i, 1848, 339, pl. viii, figs. 1 and la.Google Scholar
page 122 note 2 Salter, , Mon. Brit. Trilob., pt. iv, 1867, pl. xxviii, fig. 12.Google Scholar
page 124 note 1 Salter, , op. cit., 1867, 185–7.Google Scholar
page 124 note 2 Warburg, , op. cit., 117–123, pl. ii, figs. 14–18.Google Scholar
page 125 note 1 Warburg, , op. cit., 123, pl. ii, 19–24.Google Scholar
page 126 note 1 Salter, , op. cit., 1867, pl. xxviii, fig. 9.Google Scholar
page 126 note 2 Portlock, , Rep. Geol. Londond., 1843, pl. x, fig. 4.Google Scholar
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page 126 note 4 Warburg, , op. cit., 1925, 117, pl. ii, figs. 14–18.Google Scholar
page 127 note 1 Reed, , Lr. Pal. Trilob. Girvan, ii, 67, pl. ix, figs. 14–16.Google Scholar
page 127 note 2 Holm, , op. cit., 133, t. viii, figs. 14–22.Google Scholar
page 127 note 3 Portlock, , op. cit., pl. x, fig. 5.Google Scholar
page 127 note 4 Salter, , op. cit., 1848, pl. viii, fig. 8; and op. cit., 1867, pl. xxviii, fig. 8.Google Scholar
page 128 note 1 Reed, , op. cit., 71, pl. x, fig. 9.Google Scholar
page 128 note 2 Holm, , op. cit., 107, t. v, figs. 1–20.Google Scholar
page 128 note 3 Salter, , op. cit., 1867, pl. xxviii, fig. 11.Google Scholar
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page 128 note 5 Salter, , op. cit., 1867, p. 199, pl. xxix, figs. 2–6.Google Scholar
page 128 note 6 Holm, , op. cit., 1886, p. 125.Google Scholar
page 130 note 1 Salter, , op. cit., 1867, pl. xxviii, fig. 6.Google Scholar
page 131 note 1 Salter, , op. cit., 1867, pl. xxx, fig. 6. (This specimen cannot be traced.)Google Scholar
page 131 note 2 Reed, , op. cit.. 1904, p. 59.Google Scholar
page 131 note 3 Ibid., 55, pl. viii, figs. 6–11.
page 131 note 4 McCoy, , Syn. Brit. Pal. Foss. Woodw. Mus., Appendix A, 1852, iv, pl. 1 E, fig. 19.Google Scholar
page 131 note 5 Salter, , op. cit., 1867, pl. xxviii, fig. 10.Google Scholar
page 132 note 1 Salter, , op. cit., 1848, pl. viii, fig. 2.Google Scholar
page 133 note 1 Warburg, , op. cit., 117, pl. ii, figs. 14–18.Google Scholar
page 133 note 2 McCoy, , op. cit., pl. l E, fig. 19a.Google Scholar