178 Notes, ii. 10 — 13. 



animals only see wTien this covering is drawn back. So also is it with the organ of 

 smell. In some animals this lies bare and exposed. But in those that have lungs it 

 is covered, and the covering is removed by the act of inspiration ; for this dilates the 

 channels and vessels." See also De Sensu, 5, 24. By saying that there is a covering 

 he probably only means that there is something analogous to the covering of the eye ; 

 this something being the contracted condition of the nasal passages, which are dilated 

 when air enters. 



25. A. accounts for the nostrils being where they are by the necessity of their 

 coinciding with the organs for admission of air ; but gives no reason why these organs 

 should be central. 



(Ch. 11.) 1. '"Man is the only animal with ears that are incapable of motion" 

 [^H. A. i. 1 1, 2). As to the use of a large concha, cf. D. G. v. 2, 8. 



(Ch. 12.) 1. Birds have no concha, neither have Reptiles. But in some birds "which 

 enjoy the locomotive or visual faculties in a less perfect degree than the rest of the 

 class, there is found a peculiar arrangement of the feathers round the external meatus, 

 which serves in some degree the office of an external ear. The Ostrich and Bustard 

 are so provided, and these birds can raise the auditory circle of plumes to catch 

 distinctly any distant sound that may alarm them. The Owls again are furnished with 

 a large crescentic flap, or valve " {Todd's Cycl. i. 308). 



2. Because ears made of hard skin would not be readily moveable. See what he 

 says in the next chapter as to moveable eyelids. 



3. Elsewhere (Z). G. v. 2, 10) it is said that external ears would not only be useless 

 but prejudicial to seals, as they would allow of the entrance of water. The true 

 teleological explanation of the absence of external ears from these animals, as also 

 from cetacea and birds, is apparently, as Hunter pointed out, that they would be a 

 hindrance to progressive motion, 



4. " The seal is as it were a stunted quadruped. For it has feet immediately after 

 its shoulder-blade, and these feet are like hands, just as in the bear. For each foot 

 has five digits, and each digit has three joints and a small nail. The hind-feet also 

 have each five digits, and joints and nails, like the fore-feet, but in shape they resemble 

 the tail of a fish " {H. A. ii. i, 14). Thus it appears that A. thought that the seal 

 had IK) humerus nor ulna, their shortness disguising their presence in the undissected 

 animal. 



(Ch. 13.) 1. The "heavy-bodied" birds are described in various passages as living 

 on the ground, being unsuited for flight, liking to roll in the dust, not constructing 

 regular nests, and frequently having spurs. Partridges, quails, pheasants, common 

 fowls, are mentioned as belonging to the group, which clearly corresponds generally 

 to our Gallinacese. 



2. In birds, aS a rule, as also in chelonia, in crocodiles, and in frogs, the lower lid 

 is much larger and more moveable than the upper one, and it is with it therefore that 

 the eye is closed in sleep. There are, however, some few exceptions. Thus in the 

 .nightjar and in the owls the upper lid is the more moveable of the two. Tliis latter 

 exception is noticed by A. elsewhere {H. A. ii. 12, 7). In many parrots also the two 

 lids are equally mobile. This is not noticed by A., who probably never saw a living 

 parrot (cf. ii. 17, Note 3). He does, however, a few sentences later, say that pigeons 

 use both lids to close the eye, which also is a correct observation. A. both here and 

 elsewhere speaks erroneously of a nictitating membrane as peculiar to birds. For, 

 though it is especially well developed in birds, yet it is to be found in numerous 

 reptiles, amphibia, and sharks, not to mention some mammals. 



