Is the _covering of the body_ like the covering of any animal yet studied? The scales are attached in little pockets, or folds, in the skin. Observe the shape and size of scales on different parts of the body. What parts of the fish are without scales? Examine a single scale; what is its shape? Do you see concentric lines of growth on a scale? Sketch a few of the scales to show their arrangement. What is the use of scales? Why are no scales needed on the head? How much of each scale is hidden? Is there a film over the scale? Are the colours in the scale or on it? =The Fins.=—Are the movements of the fish active or sluggish? Can it remain stationary without using its fins? Can it move backward? How are the fins set in motion? What is the colour of the flesh, or muscles, of a fish? Count the fins. How many are in pairs? (Fig. 209.) How many are vertical? How many are on the side? How many are on the middle line? Are the paired or the unpaired fins more effective in balancing the fish? In turning it from side to side? In raising and lowering the fish? In propelling it forward? How are some of the fins useful to the fish besides for balancing and swimming? The hard _spines_ supporting the fins are called the fin rays. The fin on the dorsal line of the fish is called the _dorsal_ fin. Are its rays larger or smaller than the rays of the other fins? The perch is sometimes said to have two dorsal fins, since it is divided into two parts. The fin forming the tail is called the tail fin, or _caudal_ fin. Are its upper and its lower corners alike in all fishes? (Fig. 228.) On the ventral side, just behind the vent, is the ventral fin, also called the anal fin. The three fins mentioned are unpaired fins. Of the four-paired fins, the pair higher on the sides (and usually nearer the front) are the _pectoral_ fins. The pair nearer the ventral line are the _pelvic_ fins. They are close together, and in many fish are joined across the ventral line. The ventral fins are compared to the legs, and the pectoral fins to the arms, of higher vertebrates. (Fig. 244.) Compare fins of fish, pages 123, 124. Make a =drawing= of the fish seen from the side, omitting the scales unless your drawing is very large.