Show oJ it NOTES ON OH THE THE- AND f 10 1 THOUGH the streams stream and nd pools in and pr near near the city abound in In numerous forms of or animal life it is safe to say that the thet ti t popular knowledge of these forms is somewhat limited This limited Emited knowledge knowledge knowl knowl- edge edle no doubt is due to the exceeding smallness of some forms and indeed r even the microscopic smallness of many others For this reason it is impossible ble to make a thorough examination without L a microscope and other instruments The study of any anyone one of our local forms of life however opens up a vast field of research which may be continued almost indefinitely with ever increasing interest i and profit t A great many of the lower or orders ers of off f aquatic animals are represented in the th the waters of our ditches and stagnant pools rJ j The Am Amoeba ba represents the lowest order as' as and the and I represent one of the higher orders The and are found in great numbers living in the thea I a streams which contain or other thickly growing plants The They li live ve mostly among the tangled roots and very rarely swim about in the open water The Th e appearance and habits of off f these two little animals are very much alike so similar are they in appearance that it is quite difficult to distinguish one from the other The mature animals animals animals ani ani- mals however can be readily identified as the full grown is much r larger than a full grown but f the young is hardly distinguishable distinguishable distin distin- r from the mature by casual observation T There ere are differences however which h separate them and place each in a differ different nt family Both of these animal forms belong to the class of the sub kingdom to t the e order IFF an and t to the the s suborder sub border A At this point in their classification they sepa separate ate the being identified with the family and the with the family The body of the mature is about six millimeters in length It is is made up of sixteen segments including including- the head and the telson Except on the t ventral side it is covered with 1 scales The seven anterior ones extend i 1 ionly ionly only to the middle of of the side the rest j of the side being covered with smaller scales while each one of the eight posterior scales extends from the extremity of one onel side over to the extremity of the other otherA 11 side The body is slightly flattened r laterally and the back is usually more 1 or less arched The animal has two pairs of antennae seven pairs of legs and three pairs of swimmerets The superior anten antennae an- an ej j ten are composed of a variable num num-i ber of s segments ranging from t twenty twenty- senty seven to thirty eight The three basal segments segments seg seg- ments are about as long as all an the other segments together The inferior antennas antennae j k kare are made up of from fourteen to twenty 14 four segments The joint join t of each segment segment segment seg- seg ment on both the superior and inferior antennas antennae is furnished with short spiny hairs The legs of the are aresi arranged in two series the four anterior t pairs pointing forward and the three P posterior pairs pointing backward All Alli the legs are composed of five joints The Then first two pairs of anterior legs are exceedingly ex- ex exceedingly well developed and are armed with st stout ut prehensile claws The lower side of the two end joints are thickly covered with hairs These well developed appendages are used by the animal in in ini grasping and holding and to a great extent extent ex ex- tent in crushing its food The second secondi two pairs of legs are of an entirely different different different dif dif- ferent form having no specially developed developed developed devel devel- parts They are tipped with slightly curved cla claws s The animal uses these legs for crawling when it is among the roots of the water plants The three posterior pairs are especially long and andt 4 slender compared with the other legs r The hip Joints hip joints however are well developed developed developed devel devel- indicating the function of these appendages that of springing These legs are tipped with small claws and are furnished with spines on both the anterior anterior anterior anter anter- and posterior sides The next set of appendages are the three thre pairs of swimmerets swimmerets swim- swim which are attached to the ventral side of the back part of the abdomen The swimmerets are compose composed of segments segments segments seg seg- ments similar to those ol ot the antennae and are entirely covered with hairs When the animal is moving freely in the water these appendages are in a a acon continuous continuous continuous con con- motion of varying rapidity The telson which is one of the distinguishing characteristics of the is made up of two long oval scales At the posterior posterior pos pos- end of each of these scale plates are two short short sharp sharp spines and on each side of these two spines is n Ja a- a single hair 1 I j Respiration is performed b by r means of like leaf gills which are attached to t the e ventral side of the body at the inside of the hip joint The gills are about the size of pin heads and are made mad of especially especially especially thin transparent tissue Around the edge of the gill runs a vein which leads into a number of cross veins running running running run run- ning laterally with the place of attach attach- ment The fluid answering as blood enters one side of the gills following around the border vein Passing from th this s side through the lateral veins it enters the opposite te side of the border vein and returns to the body i The digestive apparatus is of a simple kind It consists of a straight tube running running run run- ning through the body there being no special development for the performing of special functions The has well developed developed- eloped eyes They are composite appearing Bunder under the microscope li like e portions of a mulberry They are situated situate in the front of the of-the the head a little outside th the peduncle of the superior a antennae tenn J In n the pre preceding e de descriptive c p paragraphs ph f C 14 j. j of the the has i also oe been l p practically ac des described rib d. d TH are however a few family d differences which ought to be given As before stated o one e of the chief differences between between between be be- tween the and the is the telson Instead of two s scale ale plates the has but one broad and furnished with but two spines The feet are armed umed with claws sharper and stronger than those of the seem to have hav passed to a more mor advanced stage of development in proportion proportion proportion pro- pro portion to the size of the animal t As to the use of these little animals in in nature but little is known only so far as s they arc of some economic value Professor Professor Professor Pro Pro- fessor Verrill in speaking of these Amphipods phi pods wh which ch abound in many parts of the country says says These small Crus Crus- are of great importance in connection connection connection con con- with our fisheries for we have found that they constitute a very very large part part- of the food of our val valuable able e edible ibl fishes j Alpha Rho fY i. i Ii fiU I i |