. Beginners' Zoology . )) Jlatzuorms, includingtapeworm and liver fluke ; 4) rotifers, whichare microscopic aquatic forms. The tapeworm is a flat worm which has lostmost of its organs on account of its parasiticlife. Its Qgg is picked up by an herbivorousanimal when grazing. The embryo under-goes only partial development in the bodyof the herbivorous animal, an ox. Thenext stage will not develop until the beef is eaten by acarnivorous animal, to whose food canal it attaches itselfand soon develops a long chain of segments called atape. Each segment absorbs fluid food through its Fig. 79.
. Beginners' Zoology . )) Jlatzuorms, includingtapeworm and liver fluke ; 4) rotifers, whichare microscopic aquatic forms. The tapeworm is a flat worm which has lostmost of its organs on account of its parasiticlife. Its Qgg is picked up by an herbivorousanimal when grazing. The embryo under-goes only partial development in the bodyof the herbivorous animal, an ox. Thenext stage will not develop until the beef is eaten by acarnivorous animal, to whose food canal it attaches itselfand soon develops a long chain of segments called atape. Each segment absorbs fluid food through its Fig. 79. — SandWorm x ? (Nereis).. Fig. 80. — Head OF Sandworm (enlarged). 50 BEGINNERS ZOOLOGY body wall. As the segments at the older end mature^^.each becomes full of eggs, and the segments becomedetached and pass out of the canal, to be dropped andperhaps picked i:p by an herbivorous animal, and thelife cycle is repeated. The trichina is more dangerous to human life than is thetapeworm. It gets into the food canal in uncooked pork(bologna sausage, for example), multiplies there, migratesinto the muscles, causing great pain, and encysts thee,remaining until the death of the host. It is believed toget into the bodies of hogs again when they eat rats, whichin turn have obtained the cysts from carcasses. Summary of the Biological Process. — An earthworm isa living machine ivJiich does work (digging and crawling;seizing, swallowing, and digesting food; pumping blood;growing and reproducing). To do the work it must havea continual 5;////;^^;^^;^. The energy for its work isset free by the protoplasm (in its microscopi
Size: 1226px × 2038px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, bookidbeginnerszoo, bookyear1922
