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Published online by Cambridge University Press: 01 May 2009
Among the Crustacea from the Coal-measures of Coseley, near Dudley, which have been lent to me for examination by Mr. Walter Egginton, are a number of specimens of a form probably identical with that described by Dr. Henry Woodward as Prœanaspides prœcursor. These specimens make it possible to supplement, in some important particulars, the original account of the species, and throw fresh light on its relations to the living Syncarida. Reasons are given below for regarding the genus Prœanaspides as a synonym of Palœocaris, Meek & Worthen.
page 488 note 1 Geol. Mag., Dec. V, Vol. V, p. 385, 1908Google Scholar.
page 488 note 2 It may be useful to give some notes on the methods that have proved most effective in the study of these fossils. A Zeiss binocular dissecting microscope was used, and the cleaning of the specimens with needles was aided by cautious applications of hydrochloric acid. The interpretation of the hollow parts is greatly facilitated by taking impressions in modelling wax, but it has to be borne in mind that these impressions of the inner surface of the exoskeleton do not give accurately the relief of the outer surface, for example, in the relation of the mandible to the side-plate of the head, as shown in Fig. 2, A. In some cases the parts of the fossil (e.g. the thoracic exopodites) are distinguished from the matrix by a difference of colour, not of relief. These are seen most clearly if the surface be wetted and a thin cover-glass placed on it.
page 490 note 1 In Anaspides the fourth thoracic (third free) somite overlaps both in front and behind. I have not been able to determine the overlap of the somites in the other recent genera.
1 Proc. Acad. Nat. Sci. Philadelphia, 1865, p. 48Google Scholar.
page 490 note 2 Geol. Surv. Illinois, iii, p. 552Google Scholar.
page 490 note 3 Mem. Nat. Aead. Sci. Washington, iii (2); Mem. 15, pp. 129–33, pl. iiiGoogle Scholar.
page 490 note 4 It is possible that Palœocaris Burnettii, Woodward, H. (GEOL. MAG., Dec. II, Vol. VIII, 1881, p. 533, Pl. XIV, Figs. 3a, b)Google Scholar, might prove to be identical with the species discussed here, but the specimen from which it was described is probably too imperfect to make sure of this.
page 493 note 1 Trans. Koy. Soc. Edinb., xxxviii, p. 787, 1896Google Scholar.
page 493 note 2 Ann. Mag. Nat. Hist. (7), xiii, p. 155, 1904Google Scholar.
page 494 note 1 GEOL. MAG., Dec. V, Vol. VIII, p. 156, 1911Google Scholar.
page 494 note 2 Mem. Nat. Acad. Sci. Washington, iii (2); Mem. 15, p. 124, pi. i.fig. la, 1886Google Scholar.
