. Outlines of zoology. Zoology. TREMATODA. '59 causes the serious disease called liver rot. The animal is flat, oval, and leaf-like, measures almost an inch in length by half an inch across the „, broadest part, varies from „ / reddish brown to greyish yellow in colour. As the word Dtstomum suggests, there are two suckers,— an anterior, perforated by the mouth ; a second, imperforate, a little further back on the mid- ventral line. There is a muscular pharynx and a blind alimentary canal which sends branches through- out the body. The nervous system consists of a ganglionated collar round the
. Outlines of zoology. Zoology. TREMATODA. '59 causes the serious disease called liver rot. The animal is flat, oval, and leaf-like, measures almost an inch in length by half an inch across the „, broadest part, varies from „ / reddish brown to greyish yellow in colour. As the word Dtstomum suggests, there are two suckers,— an anterior, perforated by the mouth ; a second, imperforate, a little further back on the mid- ventral line. There is a muscular pharynx and a blind alimentary canal which sends branches through- out the body. The nervous system consists of a ganglionated collar round the pharynx, from which nerves go forward and backward; of those which run backward, the two lateral are most important. Although the larva has eye spots to start with, there are no sense organs in the adult. The body cavity is repre- sented by a few small spaces. Into these there open the internal ciliated ends of much-branched excretory tubes, which unite posteriorly in a terminal vesicle opening to the Fig. 70.—Structure of liver fluke.—After Sommer. From ventral surface. The branched gut [g.) and the lateral nerve () are shown to the left, the brandies of the excretory vessel () to the right. m., Mouth; ph., pharynx; g:t lateral head ganglion ; , ventral sucker ; , position of cirrus sac ; an arrow indicates the ex- cretory aperture. The reproductive system is hermaphrodite and complex. From much-branched testes, spermatozoa pass by a pair of ducts (vasa deferentia) into a seminal vesicle lying in front of the ventral Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Thomson, J. Arthur (John Arthur), 1861-1933. Edinburgh, Glasgow and London, H. Frowde and Hodder & Stoughton
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
