The royal natural history . and stretching back-wards side by side with the narrow intestine,which terminates close to the large cup-shapedsucker. The structure of the organs that have been just described explains theutility of the leech as a blood-letter. The creature adheres to the spot uponwhich it is placed by means of its front sucker, which has the mouth in the middleof it. The jaws are then brought to bear upon the skin and start saving theirway into it, while the blood that flows from the wound passes into the sacs of thestomach until they are all filled ; and since the walls of the bo
The royal natural history . and stretching back-wards side by side with the narrow intestine,which terminates close to the large cup-shapedsucker. The structure of the organs that have been just described explains theutility of the leech as a blood-letter. The creature adheres to the spot uponwhich it is placed by means of its front sucker, which has the mouth in the middleof it. The jaws are then brought to bear upon the skin and start saving theirway into it, while the blood that flows from the wound passes into the sacs of thestomach until they are all filled ; and since the walls of the body as well as thoseof the alimentary canal are highly clastic, it is easy to understand how the creatureis able to expand to two or three times its normal size. Some of the structuralpoints enumerated above are shown in the illustration on the next page, in which1 is the alimentary canal, with the oesophagus (a) and the sacs of the stomach (hand c); 2 is the head end showing the eye-spots; and 3 is part of one of the A, Myzostoma gigas from below : /., portion OF ARM OF A (Antedoil), SHOW-ING THE SWELLINGS PRODUCED BY M y:udoma. 442 WORMS. Leeches are found in marshes and ponds with a bottom of mud or clay, andovergrown with weeds. They cannot live long out of water and die as soon as the skin dries, though for sometime they may protect them-selves from this by theexcretion of slimy day, and especially inwarm weather, they swimabout with liveliness, but atnight and in dark, foggyweather, or on cold days theyremain quiet and curled up,and in the autumn theybury themselves deep in themud. They feed largelyupon the blood of fishes,frogs, or mammals, but some-times, in cases of necessity,devour each other. Afterpairing in the spring, thesuctional leeches bore into thesoft spongy ground just abovethe level of the water, and at the end of July or thereabouts begin to form theircocoons or egg-cases, one of which is shown at D in the above illustration. Thes
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Keywords: ., bookcentury1800, booksubjectnaturalhistory, booksubjectzoology
