Show rt i if f Fluke Worms 1 r THE department of Biology is indebted ti to Mr E. E A. A Taylor for some fine speCimens specimens specimens mens of fluke worms taken by him from the liver of a sheep The fluke worm belongs to that class of worms known as the or flat worms and like many other worms of this class is parasitical parasitical parasitical para para- in its habits The life history of this interesting worm like a ring has no special beginning or end but we we will take the egg as a starting point The egg is laid in the alimentary canal canal cat ca ca- t nal of a sheep and is finally expelled f from the body of the sheep If now by by- any chance this egg falls into the water a young worm is soon hatched and be becomes becomes becomes be- be comes a swimming free-swimming form in the water If within twenty-four twenty or thirty hours after it has left the egg the young worm comes into contact with a snail it bores its way into the snail nail and takes up its abode in its body Here it undergoes undergoes undergoes un un- a rapid development and reaches what is known as the redia stage of its existence In this stage it produces by internal budding a number of young ones These young are known as These soon themselves in little sacks within the snails snail's body where they remain for an indefinite length of time If the snail chance to crawl out on the grass and be ea eaten ten by a sheep or should the sheep drinking from the pond chance to swallow swallow swallow low one of these snails the are introduced into the body of the sheep Here they undergo a further stage of development and after boring through the alimentary canal pass into the liver of the sh sheep ep where they are know as fluke worms Here they reach their full development and reproduce themselves themselves themselves them them- selves by eggs which pass into the in intestines intestines intestines in- in of the sheep and when they are expelled from the intestines the circle of life begins anew We can feel quite sure that all of the parasitical worms have descended from parasitical non-parasitical forms and the fluke worm bears as much evidence of it as any parasitical worm with which we are acquainted acquainted acquainted ac ac- for until it reaches the stage of its existence spots eye-spots are plainly visible and it is not impossible that even in the middle form some trace of eyes can be found As its mode of life renders eyes absolutely useless we can account for the presence of eyespots eyespots eyespots eye- eye spots only on the supposition that it has descended from living free-living forms which used their eyes as eyes are used by other worms In some parts of Europe fluke worms have done dorie immense damage to to sheep c interests In England some fifteen years ago it is estimated that at least twelve l million dollars dollar worth of sheep died in a single year from the ravages of these worms In this country t the e worms are not especially injurious but should they become injurious it is highly probable that by a thorough investigation of their habits means would be found whereby whereby where where- t by their ravages would be readily checked W. W L II |