^{page 450 note 1} Figures and Descriptions of Canadian Organic Remains, Dec. ii., Graptolites of the Quebec Group, Montreal, 1865.

^{page 450 note 2} Ueber Graptolitheu, etc., Breslau, 1851.

^{page 450 note 3} Die Versteinerungen der Grauwackenformation in Sachsen: I. Graptolithen, p. 17

^{page 450 note 4} Monograph of the British Graptolitidæ, p. 63.

^{page 451 note 1} “On Dicellograptus, a new genus of Graptolites,” Geol. Mag. Vol. VIII. (1871), No. 1.Google Scholar

^{page 451 note 2} “Monograph of the British Graptolitidæ” (1872), p. 55.

^{page 451 note 3} “Notes on British Graptolites,” Geol. Mag. Vol. X. (1873), p. 501.Google Scholar

^{page 452 note 1} Monograph of the British Graptolitidæ, p. 63

^{page 452 note 2} “On Dicellograptus,” Geol. Mag. Vol. VIII. (1871), p. 22.Google Scholar

^{page 452 note 3} “On the Graptolites of the Arenig and Llandeilo Rocks of St. David's,” Quart. Journ. Geol. Soc. vol. xxxi. (1875), p. 640.Google Scholar

^{page 453 note 1} The question of the angle of divergence appears to me to be a comparatively simple matter. Leaving out of consideration the two sides of the branches, the angle of divergence is that formed by the axial lines of the branches at their meeting-point in the sicula. Assuming the two branches to grow quite straight out from the sicula, there will be no angle of divergence (0°), and the celluliferous margins will be in contact;—then, as the branches diverge, sweeping round the imaginary circle of which the sicula is the centre (of course in the direction of the non-celluliferous margin, as otherwise they would have to cross each other), these axial lines will form gradually increasing angles, until the dorsal margins come close together, when we get 360° as in fig. 5. Roughly speaking, the angles shown in the figures would be, for fig. 2, about 90°; fig. 3, about 270°; fig. 4, 360°, and 330°; and for fig. 5, 360°.—W. S. D.

^{page 455 note 1} “Pterograptus, ett nytt Graptolitslägte,” Öfv. Kongl. Vet. Ak. Förh. 1881, No. 4.

^{page 457 note 1} Geological Survey of Canada: Graptolites of the Quebec Group, Montreal, 1865, and Introduction to the Study of the Graptolites, Albany, 1868.

^{page 458 note 1} Ann. Mag. Nat. Hist. Jan. 1882, pp. 54–57.

^{page 458 note 2} Journ. Quek. Micr. Club, vol. i. p. 161.Google Scholar

^{page 458 note 3} Ann. Mag. Nat. Hist. Soc. ser.5, vol. ix. (1882), pp. 54–57.Google Scholar

^{page 459 note 1} Ann. Mag. Nat. Hist. (1873), ser. 4, vol. xi., pp. 140.Google Scholar