CHAP. XIII.] LOWER ANIMALS. 205 



The mere keenness, or discriminative refinement of the 

 several sensory endowments in different animals, is subject 

 to great variation the extremes being both far below and 

 far above the human standard. 



Thus the Sight impressions of certain Worms and 

 Mollusks, obtained even at their best through simple ocelli, 

 can only be regarded as of the most vague and general 

 description, and probably more or less wanting in any 

 such accompaniment as constitutes the conscious side of 

 our own visual impressions. But how different is this 

 from the same mode of sensorial activity in Birds. In a 

 large majority of them, their power of vision seems far to 

 transcend that of man or other animals, both in regard to 

 range and keenness of discrimination . Sight is unques- 

 tionably the dominating sense of Birds. 



"A hawk," observes Buffon, "during its ae v ial soaring, will 

 discern a lark upon a clod of earth, coloured almost exactly like 

 itself, at twenty times the distance at which a man or a dog can 

 perceive it. A kite, having soared to an elevation beyond our 

 ordinary vision, can distinguish lizards, field mice, and small birds, 

 and select those upon which he chooses to pounce." 



Again, the majority of invertebrate animals seem to 

 have extremely little power of Hearing or discriminating 

 different kinds of sounds.* Thus Sir John Lubbock 



says,t 



" Approaching an Ant which was standing quietly, I have 

 over and over again made the most shrill noises I could using a 

 penny pipe, a dog-whistle, a violin, as well as the most piercing 

 and startling sounds I could produce with my own voice, but with- 

 out effect. At the same time I would by no means infer from this 

 that they are really deaf, though it certainly seems that their 

 range of sounds is very different from ours. We know that certain 



* See " Nature," 1878, pp. 540 and 568. 



f " Journal of Linn. Soc." (Zool.), vol. xiii. p. 244. 



