15G TRILOBITBS OF GIRVAN. 



3. Phacops (Phacopidella) downingiae (Murchison), 1839. 



1822. Calymene rnacrophthalma, Brongniart, Hist. Nat. Crust. Foss., pi. i, fig. 4 {non fig. 5) 

 1836. Cah/mene rnacrophthalma, Buckland, Geol. and Min., pi. lxiv, fig. 5 (non fig. 4). 



1839. Calymene downingiae, Murchison, Silur. Syst., p. 655, pi. xiv, fig. 3. 



1830. Axn jili us subcaudatus and A. cawdori, Murchison, ibid., p. 655, pi. vii, figs. 9, 10. 



1840. Calymene downiiigitr, Milne Edwards, Crust., vol. iii, p. 324. 

 1843. Acaste downingiae, G-oldfuss, Neues Jahrb., p. 563. 



1843. Phacops rnacrophthalma, Burmeister, Organ. Trilob , pp. 139, 140. 



1845. Phacops downingiae, Emmrich, Neues Jahrb., p. 40, pi. i, fig. 2 (translated in Taylor's 



Scientific Memoirs, 1846, vol iv, pi. iv, fig. 2). 



1848. Phacops downingiae, Salter, Mem. G-eol. Surv., vol. ii, pt. i, p. 336, pi. v, figs 2 — 4. 



1851. Phacops downingiae, M'Coy, Synops. Pal. Foss. Woodw. Mus., p. 160. 



1853. Phacops downingiae, Salter, Mem. G-eol. Surv., dec. vii, pi. i. 



1854. Phacops downingiae, Morris, Cat. Brit. Foss., 2nd ed., p. 113. 

 ? 1854. Phacops breviceps, Angelin, Pal. Scand., p. 12, pi. ix, fig. 4 a. 



1857. Phacops downingiae, Nieszkowski, Archiv Naturk. Liv.-, Est.-, Kurl., ser. 1, vol. i, p. 531. 



1859. Phacops downingiae-, Murchison, Siluria, 2nd ed., pi. xviii, figs. 2 — 5. 



1864. Phacops {Acaste) downingiae, Salter, Mon. Brit. Trilob., p. 24, pi. ii, figs. 17 — 36. 



1873. Phacops downingiae, Salter, Cat. Camb. Silur. Foss. Woodw. Mus., p. 131. 



? 1874. Phacops dubius, Steinhardt, Die preuss. Geschieb. gef. Trilob., p. 14, pi. i, fig. 7. 



1875. Phacops downingiae, Baily, Char. Brit. Foss., p. 68, pi. xxiii, fig. 6. 



? 1876. Phacops downingiae, Armstrong and Young, Cat. West. Scot. Foss., p. 16. 



1876. Phacops downingiae, Schmidt, Verh. Min. Gesell. S. Petersb., n. s. vol. x, p. 15, pi. i, fig. 1. 



1877. Phacops {Acaste) downingiae, Woodward, Cat. Brit. Foss. Crust., p. 51. 



1878. Phacops downingiae, Nicholson and Etheridge, Mon. Silur. Foss. Girvan, fasc. i, p. 98. 

 1881. Phacops downingiae, Schmidt, Eev. Ostbalt. Silur. Trilob., pt. i, p. 75, pi. i, fig. 2 ; pi. xi, fig. 18. 

 1885. Phacops downingiae, Lindstrom, Forteckn. Gotl. Silur. Crust. (Ofv. Iv. Svensk. Vet. Akad. 



Forhandl., no. 6), p. 42. 

 1888. Phacops downingiae, Wigand, Zeitschr. deutsch. Geol. Gesell., vol. xl, p. 41, pi. vi, figs. 2, 3. 

 1890. Phacops (Acaste) downingiae, Pompecki, Die Trilobit. f. Ost. West-preuss Diluv. Geschieb., 



p. 19, pi. i, figs. 27, a—c. 

 1899. Phaenjis downingiae (e. j).), Mem. Geol. Surv., Silur. Rocks Brit., vol. i, Scotland, pp. 529, 



530, 689. 



Remarks. — It must still remain doubtful whether the true P. downingiae oecurs 

 in the Grirvari area. I have seen poor specimens from Woodland Point which may 

 possibly be referable to it ; but, as Nicholson and Etheridge remarked (M, fasc. i, 

 1 878, p. 98), the specimens usually attributed to it belong to P. stokesi (= P. elegans). 

 The species is included by me in the subgenus Phacopidella. 1 



Collections. — Mrs. Gray; Museum of Practical Geology. 



Horizons and Localities. — Saugh Hill Group (M. Llandovery): Woodland 

 Point. ? Wenlock Series: Knockgardner, Straiton. 



1 The opinion expressed by Drevermann ('Neues Jahrb. f. Miner.,' 1906, vol. ii, Ref. p. 139) 

 t li;it t his subgeneric name is sup'-rlluous, seems based on a strange misapprehension of ils plivlogenetic 

 significance, 



