. Civic biology; textbook of problems, local and national, that can be solved only by civic coöperation. Biology. '.IA :]10 ^^^^HS^^^fT mm HHB P vH H£^^Htf( â¢i Yf^i 15 ⢠''â >:-Sm j" ^« ^Bi^ 1 :^iH ^^^K^ ^ ^^H â¢% ^ ^^ Fig. 151. Coininon tree frocr Photograph l)y Millett T. Thompson to frogdoin in a i)ond :>(! feet l>y ;», havinj; a <l«'i»tli of 2 feet of ; As eggs of leopard frogs, pickerel frogs, and woo(jssiltilities of ]i\('-fot>d jiroduction. Ill addition to their uses, actual and l»otential, as insect trajis, frogs hav** com- mercial v
. Civic biology; textbook of problems, local and national, that can be solved only by civic coöperation. Biology. '.IA :]10 ^^^^HS^^^fT mm HHB P vH H£^^Htf( â¢i Yf^i 15 ⢠''â >:-Sm j" ^« ^Bi^ 1 :^iH ^^^K^ ^ ^^H â¢% ^ ^^ Fig. 151. Coininon tree frocr Photograph l)y Millett T. Thompson to frogdoin in a i)ond :>(! feet l>y ;», havinj; a <l«'i»tli of 2 feet of ; As eggs of leopard frogs, pickerel frogs, and woo(jssiltilities of ]i\('-fot>d jiroduction. Ill addition to their uses, actual and l»otential, as insect trajis, frogs hav** com- mercial values which threaten their exter- mination in many localities. In souie jdaces small ones hring from Si to S'')(I per 1()(» for fish l>ait. The frog is the animal luost commonly used for laboratory studv the world ovei-; frogs used for this purpose hring from .")() cents to $o per do/.en. More- over, while they were rarely used for food a few years ago, frogs' legs have now he- come a well-known delicacy. "The meat is white, delicate, and very wholesome and ; Hence catching frogs for mar- ket often yields good profit, and it affords a mildly humorous form of outdoor sport. As these values come to he recognized, valuable sj^'cies can ]>e protected by closed seasons (from the opening of spring until after they spawn), local waters can be kept stocked to their full capacity, and an abundant crop can be secured each year. Some special problems. 1. in a pond stocked with bullfrogs, how can we feed so as to prevent cannibal- ism and thus secure the greatest numl)er of large specimens from a given area ? 2. IIow^ can the largest number of toads be reared from a pool a foot square and a foot deei)? (^^^â have one record of :{1);JS from April to August; the main foods were alga% dog biscuit, and fresh fish.) ^3. Are toads beinc: exterminated from agricultural districts bv drain- ing their breeding pools, by farm animals, and by
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Keywords: ., bookleafnumber341, bookpublisherbostonginn, booksubjectbiology
