22 DEVONIAN FAUNA. 



P. venustus 1 and in P. complanatus? Barr., which are the most similar, the 

 glabella does not quite touch the border and is somewhat narrower, and the eye is 

 set less forward. The pygidia of these two species are very similar to those we 

 have referred to the present species. The axis of the pygidium of P. eremita, 

 Barr., 8 is much more conical, and the outline of that of P. curtus, Barr.,* is wider. 

 P. BoJiemicus, Barr., 5 and P. my ops, Barr., 6 are the only Bohemian species that 

 agree with it in the glabella reaching the border ; but the first of these differs in 

 being much more convex, and in having minute cheek-spines and a more rounded 

 eye, and the second in having no cheek-spines, a very short neck-lobe, and in 

 being very much wider. In P. superstes, Barr., 7 the glabella is much smaller and 

 does not approach the border, and the eye is large. 



Neither P. Barrandei, F. A. Rom., 8 nor P. orbicularis, F. A. Rom., 9 can be 

 mistaken for our species ; not only have they more rounded glabella? and much 

 longer cheek-spines, but they differ from it in many other respects. In P. pictus, 

 Giebel, 10 the glabella seems much narrower and more rounded. 



Of American forms P. canaliculatus, Hall, 11 P. Rowi, Hall, 12 and P. Prouti, 

 Hall, 13 all differ from the present form in having the glabella narrower and more 

 triangular. The latter may also be distinguished by its broad, flat border. 



Professor Phillips has figured a fragment of the head-shield of this species, 

 but without giving either description or locality. 



2. Proetus subfeontalis, Whidborne. PI. II, figs. 11, 12. 



1889. Peoetus sttbfeontalis, Whidb. Geol. Mag., dec. 3, vol. vi, p. 29. 



Description. — Head moderately convex, smooth, and small. Glabella finely 

 granulated, flattened, highest behind, indistinctly depressed along the centre of 



1 1852, Barr., ' Syst. Sil. Bohem.,' vol. i, p. 467, pi. xvii, figs. 1—6, Ft. E. 



2 Ibid., p. 463, pi. xvii, figa. 34—41, Ft. F. 



3 1878, Kayser, ' Abbandl. geol. Specialk. von Preussen,' Band 2, pt. 4, p. 15, pi. i, fig. 2 — 4 ; 1852, 

 Barr., « Syst. Sil. Bohem,' vol. i, p. 462, pi. xvii, figs. 9, 10, Et. F. 



4 1852, Barr., ' Syst. Sil. Bohem,' vol. i, p. 462, pi. xvii, figs. 7, 8, Ft. F. 



5 Ibid., p. 452, pi. xvi, figs. 1—15, Ft. F. 



6 Ibid., p. 442, pi. xv, figs 20—22, Ft. F. 



7 1878, Ibid., vol. i, Supplement, p. 16, pi. xvi, figs. 4, 5, Ft. G. 



8 1850, F. A. Eom., 'Beitr.,' pt. 1, p. 20, pi. iii, fig. 33. 



9 Ibid., p. 20, pi. iii, fig. 34. 



10 1855, F. A. Eom., « Beitr.,' pt. 3, pi. xvi, fig. 13. 



11 Hall, 'Pal. N. T.,' vol. vii, p. 107, pi. xx, figs. 10 and 11, and pi. xxiii, figs. 10, 11. 



12 Ibid., p. 119, pi. xxi, figs. 2—6, 24—26, and pi. xxiii, figs. 24—29. 



13 Ibid., p. 126, pi. xxiii, figs. 16—18. 



