THE SENSORI-MOTOK SYSTEM 11 



Mobility Patterns. Animal movements, then, fall into 

 generalised and individualised patterns: first those of the body 

 as a whole (locomotion), and then those of the parts of the body. 

 We shall take the more complex patterns first, as these will be 

 the more familiar to the reader. There are the walking, running, 

 and leaping of quadrupeds; the walking and running of flightless 

 birds (which are bipedal movements); and the leaping movements 

 of arboreal quadrupeds, such as monkeys. There is the flight 

 of birds and insects (two rather different types), the flight of 

 bats and squirrels, and the incipient flying movements of some 

 fishes. Next, take the movements of locomotion in water: the 

 swimming of typical fishes, seals, and whales; the swimming of a 

 dog or horse ; and the swimming and diving movements of birds. 

 Very different from these are the swimming of crustaceans, such 

 as copepods; the bizarre leaping movements of a lobster or 

 scallop ; or the swimming of a cuttlefish or squid. Burrowing, as 

 in the cases of moles, earthworms, ants, and fossorial wasps, is an 

 entirely different kind of movement, and so is the creeping of a 

 slug or a centipede. The extremely limited locomotion of a 

 mussel or cockle is different again, and still more so the creeping 

 of a starfish. Among microscopic animals we have the peculiar 

 movements carried out by cilia, as in the cases of flagellate 

 organisms, infusoria, rotifers, or even spermatozoa. 



All these are categories (generalised patterns) ; thus the same 

 kinds of locomotory movements are made by all typical fishes, 

 but the swimming of a herring or mackerel shows minor differ- 

 ences from that of a sole or plaice, and so we have subcategories. 

 Again, the patterns may be specific ones ; thus the movements of 

 a panther are rather different from those of a bear. Or they may 

 be subspecific (in the zoological sense); thus the walk of an 

 Airedale differs from that of a fox terrier. And, finally, they 

 may be individual; thus the "carriage" of a man or woman 

 that one knows well is characteristic of that person, and no one 

 else. 



So also with postures and attitudes, and with the movements 

 of the limbs and other parts of the body that are used in defence, 

 aggression, etc. Thus there are biting, slashing, cutting, grind- 

 ing, and gnawing movements of jaws and teeth; clawing move- 

 ments like those of a cat or a bear; goring and tossing and butting 

 actions of horns ; the use of spines, as in a sting ray ; the lateral 

 swinging movements of the tail, as in a crocodile; crushing and 



