Show doP TWO T INTI INTERESTING Th STING WORMS IT is no easy task for the modern zoologist to define the term worm As now used the group includes forms of very diverse structure provisionally placed in one sub kingdom m known as Vermes Diverse as these forms are they have a few points in common Among these the most striking is a soft elongated body without jointed append append- 4 ages The bod body is bilaterally Asymmetrical symmetrical sym metrical and may mayor or may not be segmented segmented segmented seg seg- or divided divide into segments or rings If the sub-kingdom sub of Vermes Vennes shall ever be be divided it is probable that the theline theline theline line of division will pass between the segmented and segmented non-segmented forms Of the severa several classes into which the I F Vermes Vennes are divided the Annelid or unquestionably rank the high high- est In this class the segmentation tation of the body or as it is technically technically technically tech tech- called reaches its highest grade of development In a typical worm of this class crass the segments succeed one another from the head to to the he tail and little difference can be observed d between any to successive ones with the exception exception exception tion of the head and the tail These two segments us usually ally differ from each other an and from the other segments of the body The segments are separated from each other by an external groove completely surrounding the body and by byan byan byan an internal diaphragm or partition extending extending ex extending ex- ex tending across the body but pierced by bythe bythe bythe the digestive tube the blood vessels and the nervous system Even the three last named systems show a succession succession r y x 1 sion of contractions one for each seg- seg ment indicating the division which which t have affected the other organs Most of the are marine i worms some live in fresh water and a afew afew few are living however only in damp earth There are two fresh wa wafer wacer r forms to which I wish to invite especial attention One of these belongs to the natural order and the family t r Its name is TuN ex t It is a slender reddish worm which lives in mud tubes in the bottom of shallow 1 ponds These worms vary in length from three fourths of ot an inch to one and anda a half hal inches T They hey live in their mud tubes head downward with the tail waving in the water thus securing securing- a supply of oxygen When they are disturbed the tail is immediately withdrawn into the tube tobe to tobe be again thrust out when the danger danger- seems to be past The food of these 4 worms consists of the decaying organic matter in the mud in which the tubes are formed The worms reproduce by means of eggs and nd it is quite probable that the eggs are set free from the body t of the parent only by hy its death and andi i decomposition f Just how long one of these worms will live is at present uncertain but colonies living in moderately warm water remain active all winter Another interesting interesting- worm belongs to the order Most of the worms of this order are marine but we appe appear r to have a fre fresh h water species The head which is not clearly separated from the body is provided with a wonderful wonderful wonderful won won- crown of cirri or hairs This worm like the lives in a tube but unlike the tube of the its tube is manufactured from small masses of organic and inorganic matter cemented cemented cemented ce ce- together by a secretion apparently apparently apparently ap ap- from the worms mouth The cirri are arranged in waving plumes five being found furd on on n each side of the head It is is probable that the cirri cirri serve the double purpose of organs of of respiration and tactile organs 1 Both of these worms are easily obtained obtained obtained ob ob- and they will live for a long time in a small aquarium if the water is occasionally changed They are thus admirably fitted for school room study i and few school rooms would be without them if teachers knew how easily they may be obtained and how helpful such things are in nature work ji jimay C. C A. A If Whiting Whiling |