. Elementary text-book of zoology. Zoology. CHJETOPODA. 367 metamorphosis. The Annelida comprise terrestrial and aquatic animal.'-, and they eat, for the most part, animal food. Many of them (Hirudinea] are occasionally parasitic. In the group of the Annelida, three principal divisions may be distinguished,—the Chcetopoda, the unsegmented Gephyrea, and the Hirudinea which are adapted for parasitism. The Hirudinea are not in any degree to be regarded as Annelida of a lower grade of organization, but they rather present, at least in the case of some organs, as alimen- tary canal, circulatory and
. Elementary text-book of zoology. Zoology. CHJETOPODA. 367 metamorphosis. The Annelida comprise terrestrial and aquatic animal.'-, and they eat, for the most part, animal food. Many of them (Hirudinea] are occasionally parasitic. In the group of the Annelida, three principal divisions may be distinguished,—the Chcetopoda, the unsegmented Gephyrea, and the Hirudinea which are adapted for parasitism. The Hirudinea are not in any degree to be regarded as Annelida of a lower grade of organization, but they rather present, at least in the case of some organs, as alimen- tary canal, circulatory and generative organs, a more complicated structure, and agree most closely with the Oligocha?ta, from which they may be D ( FIG. 296.—Grubea fusi- fera (after Quatre- fages). Ph. pharynx D, alimentary can;il ; C, cirri; F, tentacles. Sub-class 1.—CHLETOPODA.* Free living Annelida, with paired tufts of seta' on the segments, frequently with distinct head, also with tentacles, eirri, and branchice. The Cha?topoda are divided externally into segments, which correspond with the rnetameres of the internal organs, and are, with the excep- tion of the anterior region, which is distinguished as the head, usually tolerably alike (fig. 296). Parapodia provided with setfe are very frequently present on the segments; their prin- cipal function is that of locomotion, but their va- rious appendages, the branchice and cirri, also discharge tactile and respi- ratory functions (fig. 297).. 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 Claus, Carl, 1835-1899; Sedgwick, Adam, 1854-1913; Sinclair, F. G. (Frederick Granville), b. 1858. New York : Macmillan
Size: 1006px × 2485px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
