. Animal biology. Zoology; Biology. support for the colony. Sometimes lime is added. Because of their superficial resemblance to corals such forms are known as coralline bryozoans. A mouth at the outer end is sur- rounded by a crown of cihated tentacles termed the lophophore, which exhibits the form of a horse- shoe when it is expanded. The U-shaped alimentary canal opens by an anus situated near the mouth and either within or without the lophophore. There are neither circulatory nor excretory organs. The nervous system consists of a central ganglion between the mouth and anus. Reproduction is
. Animal biology. Zoology; Biology. support for the colony. Sometimes lime is added. Because of their superficial resemblance to corals such forms are known as coralline bryozoans. A mouth at the outer end is sur- rounded by a crown of cihated tentacles termed the lophophore, which exhibits the form of a horse- shoe when it is expanded. The U-shaped alimentary canal opens by an anus situated near the mouth and either within or without the lophophore. There are neither circulatory nor excretory organs. The nervous system consists of a central ganglion between the mouth and anus. Reproduction is both sexual and asexual, the latter taking place by bud- ding. These animals are either monecious or diecious. The eggs are fertilized in the coelom and is "somewhat similar. develop in a modified portion of the body cavity ^^^l^^^j^^l^^lHistir^" called an ooecium which serves as a brood pouch, by the courtesy of The The larva is in many respects like a trochophore. Macmiiian Company.) •^ ^ Natural size. Certain species produce nidividuals of a peculiar type called avicularia. These are highly modified forms possessing a pair of strong jaws, which probably are used in defense. Fig. 102.—a colony of marine bryozoans, Bugula turbinata Alder. A British species; an American species, Bugula turrita (Desor), Lophophore Av/cc//arr/u/rr, jaws c/osed Musc/e -^o boofy wa/J Ovary Sto/r7ach Furicu/us Ooec/u/7^ Pharynx Anas. EsophagfU-ff Avicu/anum, Jaws oper /vfasc/e to boc/y wa// S-f-omach Ovary Funr'cc//(js Testes Fig. 103.—Bugula avicularia (Pallas), a European species. Two zooids are shown, the one at the left entire, that at the right turned 90 degrees to the first and sectioned. Two avicularia are shown, one with the jaws closed and the other with them open. An ooecium is also included in the figure. {Redrawn from Parker and Haswell, "Text-book of Zoology," somewhat modified.) Much Please note that these images are extracted from scanned page im
Size: 1363px × 1833px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcoll, booksubjectbiology, booksubjectzoology
