the influence of natural selection. Such an investigation has been attempted, and such a result apparently obtained by Mr. Cameron, in his search for "the origin and purpose of the horns and antlers of ruminants." He concludes "that the horns and antlers of ruminants are the result of a defensive adjustment in biological answer to carnivorous teeth and claws, and consequent upon the relations of destroyer and destroyed which obtained between carnivores and ungulates throughout Tertiary time.... Their historical appearance in the Miocene age of the Tertiary period is contemporaneous with a vast extinction of hornless ungulate families, and their subsequent development in an ascending scale corresponds with the gradual thinning out of unarmed ungulate genera, and the gradually increasing destructive pressure upon those, whether armed or unarmed, that survived. Their evident loss of calibre since palæolithic times may be traced chiefly to the coming of man with missile weapons, which, in altering the character of the destroying agency, discounted the value of cranial armature in the struggle for life."[1]
It is a remarkable fact with these Phasmidæ that giant forms are said to have existed even in the Carboniferous fauna. Among other Orthoptera belonging to that era were "the giant Walking-sticks recently brought to light from the coal-measures of France, the Titanophasma fayoli, which measure in length (in one specimen) upwards of twelve inches, and are therefore, by linear measure, very nearly the largest of recent as well as fossil insects."[2] It is necessary, however, to observe that much caution must be exercised in the identification of these fossil remains. Dr. Sharp is at least sceptical, for he writes:—"In the Carboniferous layers of the Palæzoic epoch there are found remains of gigantic insects that may possibly be connected with our living Phasmidæ."[3] The same writer, however, has subsequently given a less undecided opinion: "Phasmidæ are insects of extreme interest; they appear to be the nearest living repre-
- ↑ Zoologist,' 3rd ser. vol. xviii. pp. 291-2.
- ↑ Heilprin, 'Geograph. and Geol. Distr. of Animals,' p. 150.—Pharnacia serratipes, from Borneo, the largest known species, is stated by Mr. Kirby to measure nearly thirteen inches from the front of the head to the extremity of the abdomen (Trans. Linn. Soc. vol. vi. (2nd ser.) p. 448).
- ↑ 'Cambridge Nat. Hist.' vol. v. p. 276.
