IQO Notes, ill. 2. 



supply of moisture is exhausted. An impatient one rushes in and gets his whole 

 plumage so bedaubed that his flight is materially impeded, and his swoop when made 

 is irresolute." 



9. This statement, so often made by A., has much truth in it. . For example many 

 insects are protected by the dull tints of their colouring, or their resemblance to vegetable 

 or inanimate objects, rendering them practically invisible to birds. But when they are 

 endowed with some more special means of defence, their colouring is often such as to 

 render them very conspicuous. The stinging Hymenoptera, for instance, are as a rule 

 showy and brilliant, and in no single instance are protected by mimicry of vegetable or 

 inanimate objects. The Chrysididas again, though stingless, can roll themselves into a 

 ball as hard and polished as if of metal, and these are most gorgeously coloured. So also 

 the foetid Hemiptera, and the ladybirds that emit fluids which are highly distasteful to 

 birds, are in large proportion gay-coloured and conspicuous (cf. Wallace, Natural Selection, 

 2nd ed. p. 69). Facts of similar significance are observable in mammalia. "Very few 

 male quadrupeds," says Darwin {Descent of Man, ii. 257), have weapons of two distinct 

 kinds specially adapted for fighting with rival males," a statement which he proceeds to 

 support by the inverse relation which obtains as a rule between the development of horns 

 and of canine teeth. 



10. The account of the Indian Ass with a solid hoof, and a single horn, was taken by 

 A. from Gtesias, who apparently did not profess himself to have seen more of the animal 

 than its astragalus. It has been plausibly conjectured that the Indian Rhinoceros {R. 

 unicornis) is the animal meant. For, though this animal has three toes, they are so 

 indistinctly separated, that the real character of the foot might easily escape a casual 

 observer, to whom the animal would moreover probably not give much leisure for ob- 

 servation. I may, however, observe that on the obelisk of Nimroud, made long before 

 the time of Ctesias, and very possibly seen by him, there is represented a rhinoceros, with 

 feet distinctly divided into toes. An argument oa the side of the supposed identification is 

 furnished by the fact that the horn of the Indian Ass was supposed to have certain 

 magical powers, so that a* cup made of it gave the drinker immunity from poison, as is 

 related by Philostratus in his life of Apollonius j while similar virtues are assigned in the 

 East to rhinoceros horn, even in the present day. Siipposing the one-homed ass of India 



•to be the Rhinoceros unicornis, may it not be that "the asses with horns" {pi ovoi -rh. 

 Kfpea e'xoj'Tes) which Herodotus (iv. 191) enumerates among the animals of Libya are the 

 two-horned rhinocerotes of Africa ? 



11. An apparent recognition of the fact so much insisted on by Bichat, namely the 

 greater symmetry of the organs of animal life, as compared with the organs of vegetative * 

 life. Cf. iii. 5, Note 4. 



12. The Oryx is probably the Leucoryx of North Africa, which is often represented on 

 Egyptian and Nubian monuments. It is supposed that some individual that had lost a 

 horn in fighting had been seen, and taken for a member of a normally one-horned species. 

 I do not think it necessaiy to suppose this ; for the Oryx, when seen in profile, has 

 wonderfully the look of having a single horn, and I once actually heard some ladies at the 

 Zoological Gardens when they came to it, cry out, ' ' Why, it has only got one horn " ! 

 The explanation of the appearance is that the horns run straight back from their origin 

 without diverging, save in the very smallest degree, to right and left. Thus when the 

 animal is seen in profile, one horn concealing the other parallel one, the appearance is 

 as though there were a single central horn. When the horns diverge widely from each 

 other, as for instance in the common ox, no such appearance is produced by a side view. 

 So long as 2000 years after Aristotle, we find Sir T. Browne asserting, in opposition 



