658 Dinosaurs of North America, pl. LXXXI, etc. 1896.

659 Mem. Amer. Mus. of Nat. Hist. I, III, 1898.

660 These and also other coordinate diagrams will be found in Mr G. Heilmann〙s book Fuglenes Afstamning, 398 pp., Copenhagen, 1916; see especially pp. 368〓380.

661 Cf. W. B. Scott (Amer. Journ. of Science, XLVIII, pp. 335〓374, 1894), 〜We find that any mammalian series at all complete, such as that of the horses, is remarkably continuous, and that the progress of discovery is steadily filling up what few gaps remain. So closely do successive stages follow upon one another that it is sometimes extremely difficult to arrange them all in order, and to distinguish clearly those members which belong in the main line of descent, and those which represent incipient branches. Some phylogenies actually suffer from an embarrassment of riches.〝

662 Cf. Dwight, T., The Range of Variation of the Human Scapula, Amer. Nat. XXI, pp. 627〓638, 1887. Cf. also Turner, Challenger Rep. XLVII, on Human Skeletons, p. 86, 1886: 〜I gather both from my own measurements, and those of other observers, that the range of variation in the relative length and breadth of the scapula is very considerable in the same race, so that it needs a large number of bones to enable one to obtain an accurate idea of the mean of the race.〝