^{page 552 note 1} Monograph on the Carboniferous Cephalopoda of Ireland (Pal. Soc.), pt. iii (1900), p. 79, pl. xxiii, figs. 5a-c.

^{page 552 note 2} Nautilus cariniferus, J. de C. Sowerby, Mill. Con., vol. v, p. 130 (1824), pl. cccclxxxii, fig. 3, excl. fig. 4. See also A. H. Foord, Mon. Carb. Ceph. Ireland (Pal. Soc.), pt. iii (1900), p. 82, pl. xxiii, figs. 1–3; pl. xxvii, figs. 2a, b.

^{page 554 note 1} In the coiled shell of a Cephalopod the ribs or striæ are said to he ‘direct’ when their direction coincides with the radius; ‘incliued’ when they are forwardly-disposed in relation to a radius; and ‘reclined’ when they are backwardly-directed in relation to the same line.

^{page 554 note 2} The sinus of the aperture at the median part of the peripheral area or venter indicating the position of the funnel or hyponome.

^{page 554 note 3} It is to be noted also that the periphery in Dr. Foord's diagrammatic transverse section of the whorl (fig. 5c) is much less convex than it is represented at either the lower or the upper part of the front view of the fossil depicted in his fig. 5b.