. Text-book of zoology for schools and colleges. Zoology. ANARTIIEOFODA. 123 are comparatively few in number, hence the modem name of the order (Gr. oligos, few; and chaite, a bristle). In the com- mon earth-worm (Lumbricus terrestris) the body is cylindrical, attenuated at both ends, and furnished with eight rows of locomotive bristles. The mouth is destitute of teeth, and opens into a gullet which leads to a muscular crop, succeeded by a second muscular dilatation or gizzard. The intestine is continued straight to the anus, and is constricted in its course by numerous transverse partitions s
. Text-book of zoology for schools and colleges. Zoology. ANARTIIEOFODA. 123 are comparatively few in number, hence the modem name of the order (Gr. oligos, few; and chaite, a bristle). In the com- mon earth-worm (Lumbricus terrestris) the body is cylindrical, attenuated at both ends, and furnished with eight rows of locomotive bristles. The mouth is destitute of teeth, and opens into a gullet which leads to a muscular crop, succeeded by a second muscular dilatation or gizzard. The intestine is continued straight to the anus, and is constricted in its course by numerous transverse partitions springing from the walls of the body-cavity. The pseudo-haemal system is well de- veloped ; and there exists in even greater numbers than in the leeches the series of segmental organs, or lateral pouches, which open externally by pores. The Naididm are chiefly noticeable on account of their power of producing fresh indi- viduals by a process of budding before they attain sexual maturity. One of the commonest of them is a little worm which occurs abundantly in many pools and streams {Tuhifex rivulorum), and which exhibits a fine red color, owing to the pseudo-hasmal system being visible through the transparent integument. Okdee III. TuBicoLA.—The Annelides included in this group derive their name from the fact that they have the power of protecting themselves by means of tubes (Lat. tuba, a tube; and colo, I inhabit). In some cases (Fig. 48) the tube is composed of car- bonate of lime, and is a genuine secretion from the body. In all the Tubieola the respiratorj' organs are in the form of branched fila- mentous external gills, in which the fluid of the pseudo-haemal sys- tem is subjected to the action of the outer water. They are, there- fore, " branchiate " Annelides. As Fig. 48.—TnWcoia. a Serpuia con- vey live in tubes, however, and cWk Sid o^'rc^™"^6 a^^wmJ do not voluntarily expose more commmis. than the anterior end of the body, the branchiae are all pl
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
