. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. Cn.^TOPODA. 867. metamorphosis. The Annelida comprise terrestrial and aquatic animals, and they eat, for the most part, animal food. Many of them {nirudinea) are occasionally parasitic. In the group of the Annelida three principal divisions may bo distinguished,âthe Chmto'poda, the vinsegmented Gephyrea, and the Hirudinea which are adapted v A . -?'' 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 t
. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. Cn.^TOPODA. 867. metamorphosis. The Annelida comprise terrestrial and aquatic animals, and they eat, for the most part, animal food. Many of them {nirudinea) are occasionally parasitic. In the group of the Annelida three principal divisions may bo distinguished,âthe Chmto'poda, the vinsegmented Gephyrea, and the Hirudinea which are adapted v A . -?'' 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 Oligochteta, from which they may be derived. Sub-class 1. * Free living Annelida, tvith 2}«'i'''6d tufts of setce on the segments, frequently tvith distinct head, also with tentacles, cirri, and hranchice. The Chastopoda are divided externally into segments, which correspond with the metameres 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 setse are very frequently present on the segments; their prin- cipal function is that of locomotion, but their va- rious appendages, the branchice and cirr/, also discharge tactile and respi- ratory functions (fig. 297). * Besides the older works of Savigny, Audonin et Milne Edwards, and Quatrefages, compare E. Grubo, " Die Fami- lien der Annelidon," Arcltiv fur Naturgesch, 1850 and 1851. E. Claparede, 'â Eecherches anatomique sur les Ann Glides, etc.," Geneve, 1861. E. Cla- parede, " Les Annelides ch(^to- podes du golfe de Naples," Geneve et Bale, 1868, also Sup- plement, 1870, and " Eecherches sur la structure des Annelides scklentalrcs," Geneve, 1873. Fr. Lcydig, I. c, also '⢠Tafeln zur vcrgl. Anatomie/' 1861. Fig. im.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanimals, bookyear1892
