. Zoology for high schools and colleges. Zoology. 180 zooLoar. with the Polyzoa, Brachiopods, and possibly the Mollusca, the latter branch being probably a modified vermian type, and with an ancestry not unlike that of the Kotifers and aberrant, generalized Polyzoa and BrachiojJoda. The classi- fication of the Rotatoria is in an unsettled state, the group probably consisting of three orders, viz. : the true Rotatoria, the BchinoderidcB, and Gastrotricha. Class III.—KOTATORIA. Worms with usually mc/re or less solid segments, very unequally developed, bearing a ciliated velum, tJie mouth opening
. Zoology for high schools and colleges. Zoology. 180 zooLoar. with the Polyzoa, Brachiopods, and possibly the Mollusca, the latter branch being probably a modified vermian type, and with an ancestry not unlike that of the Kotifers and aberrant, generalized Polyzoa and BrachiojJoda. The classi- fication of the Rotatoria is in an unsettled state, the group probably consisting of three orders, viz. : the true Rotatoria, the BchinoderidcB, and Gastrotricha. Class III.—KOTATORIA. Worms with usually mc/re or less solid segments, very unequally developed, bearing a ciliated velum, tJie mouth opening into amastax ; sexes sepa/rate, the males much smaller, m/rre rudim^ntai-y than the females. A small nenous ganglion. No circulatory apparatus, but with a voluminous excre- tory (water-vascular) organ. (Albertia, Asplanchna, Hydatiua, Bracliionus, Rotifer, and the highest form, Flosoulavia.) Lahoratm-y Work.—The Rotifers can only he studied whUe alive and as transparent objects. Little is known about the American species. Class IV.—Poltzoa (Moss Animals). The Polyzoa, though not commonly met with in fresh water, are among the commonest objects of the seashore. They are minute, almost microscopic creatures, social, grow- ing in communities of cells (called poly- zoaria or corms), forming patches on sea- weeds and stones (Fig. 134, Membraoiipora solida Pack.). Certain deep-water species grow in coral-like forms (Fig. 125, Myrio- zoum subgracile D'Orbigny), while the chitinous or horny Polyzoa (Fig. 126, Halophila borealis Pack.), are often mis- Pig. 124.—Cells of Sea- taken for sea-weeds on the one hand, and ma, en arge . Sertulariau Hydroids on the other. From their likeness to mosses the name Bryozoa was given to the group by Ehrenberg, a year after Thompson (1830) had called them Polyzoa, so that the latter name has Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and app
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Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
