. An introduction to zoology : for the use of high schools . tumps (parapodia), which may also carry feelers,gills, or protecting scales. The marine Annelids are either car-nivorous in their habits, living a free life, and swimming orcreeping about the seashore, or sedentary forms, which buriowin the sand (Fig. 149), or live in tubes of chitin or sand or lime,which are constructed with the aid of secretions from the skin. HIGH SCHOOL ZOOLOGY. 221 The order to which the earthworm belongs, however,(Oligochseta) chiefly includes fresh-water (limicolous) or teres-trial (terricolous) worms, where t
. An introduction to zoology : for the use of high schools . tumps (parapodia), which may also carry feelers,gills, or protecting scales. The marine Annelids are either car-nivorous in their habits, living a free life, and swimming orcreeping about the seashore, or sedentary forms, which buriowin the sand (Fig. 149), or live in tubes of chitin or sand or lime,which are constructed with the aid of secretions from the skin. HIGH SCHOOL ZOOLOGY. 221 The order to which the earthworm belongs, however,(Oligochseta) chiefly includes fresh-water (limicolous) or teres-trial (terricolous) worms, where the bristles are few in number,and lodged in setigerous follicles, there being no parapodia, norappendages of the natuxO of feelers or gills. The Limicolse aresmall forms living for the most part in the mud at the bottomof ponds or streams. Son\e of them, the NaididcB, are parti-cularly remarkable on account of their reproducing themselvesby budding, so that they are often found in chains, stillattached to each other. They live chiefly on decaying vegetable. Fi^. 149.—Marine lob-worm. {Arenicola piscatorum).The bunches of setae are more apparent in front of the gills than behind. matter, but one species of Chcetogaster lives a parasitic life inthe lungs of various pond-snails. The earthworm {^Lumhricwsterrestris) is the most familiar of the Terricolse ; its setse are notconspicuous, but each segment carries eight, disposed in fourgroups. One region of the body is often swollen and noticeable*bearing the clitellum; it furnishes a cocoon in which the eggsare developed. The researches of Darwin proved the earth-worm to be of the first importance in the loosening of the soiland the formation of mould. This is effected in the course ofits burrowing, which it does partly by separating the particlesof earth, partly by swallowing them. Although no special respir-atory organs are present, yet the skin is traversed throughoutby capillary vessels, which bring the blood close to the surfa
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1889
