^{page 538 note 1} Smiths. Misc. Coll., vol. liii, p. 249, 1910Google Scholar.

^{page 538 note 2} Walcott, , Proc. Wash. Acad. Sci., vol. vii, 1905; op. cit., 1910, p. 254Google Scholar.

^{page 538 note 3} Op. cit., 1897, p. 191Google Scholar.

^{page 538 note 4} Geol. Mag., 1902, p. 539Google Scholar.

^{page 538 note 5} Op. cit., 1910, p. 254Google Scholar.

^{page 538 note 6} Palæontologia Indica, ser. xv, vol. vii, p. 9, 1910Google Scholar.

^{page 539 note 1} Beecher, , op. cit., 1897, p. 191Google Scholar.

^{page 539 note 2} Cf. Dollo, , La Paléontologie Ethologique, Bruxelles, 1910, p. 415Google Scholar.

^{page 539 note 3} Ibid., p. 409.

^{page 539 note 4} Op. cit., 1897, p. 189Google Scholar.

^{page 539 note 5} Type species, Ptychoparia (Conocephalites) striata, Emmrich.

^{page 539 note 6} Matthew, G. F., Trans. Roy. Soc. Canada, vol. xi, p. 144, 1893Google Scholar.

^{page 540 note 1} Monogr. Palæont. Soc., 1907, p. 51Google Scholar.

^{page 541 note 1} Amer. Journ. Sci., vol. iii, p. 195, 1897Google Scholar.

^{page 541 note 2} Op. cit., 1904, p. 74Google Scholar.

^{page 541 note 3} Zittel, 's Textbook, 1913, p. 715Google Scholar.

^{page 541 note 4} Op. cit., 1913, p. 716Google Scholar.

^{page 541 note 5} Palœontologia Indica, 1910, p. 10Google Scholar.

^{page 541 note 6} Cambrian Fossils of Yellowstone Park, Monogr. 32, U.S.G.S., 1899, p. 460Google Scholar.

^{page 541 note 7} Op. cit., 1898Google Scholar.

^{page 542 note 1} Trans. Roy. Soc. Canada, ser. III, vol. v, p. 118, 1911Google Scholar.

^{page 543 note 1} Geol. Mag., 1902, p. 532Google Scholar.

^{page 543 note 2} Geol. Mag., 1912, p. 202Google Scholar.

^{page 543 note 3} Vide Reed, F. R. C., Monogr. Palæont. Soc., 1903, pl. ivGoogle Scholar.

^{page 543 note 4} It is conceivable that the absence of facial suture in Harpes is a case of retention of protoparian conditions.

^{page 544 note 1} Cf. Dollo, vide supra.

^{page 544 note 2} Op. cit., 1897, p. 197Google Scholar.

^{page 544 note 3} Op. cit., p. 196Google Scholar.