. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. IIYDROZOA—Sll'HOXOPIIOBA. 243 Order 2.—SIPHONOPHORA.* Free-swimming polymorphous hydroid-stocks with contractile stem, with polypoid nutritive indi- viduals and medusoid buds, usually also with nectocaly- ces, hyrophytticti and dactylo- zooids. Morphologi- cally the Sipho- nophora are directly allied to the hy- droid-stocks; but they possess to a much greater extent than the latter the characters of individuals, in consequence of the highly developed poly- morphism o f their polypoid and me
. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. IIYDROZOA—Sll'HOXOPIIOBA. 243 Order 2.—SIPHONOPHORA.* Free-swimming polymorphous hydroid-stocks with contractile stem, with polypoid nutritive indi- viduals and medusoid buds, usually also with nectocaly- ces, hyrophytticti and dactylo- zooids. Morphologi- cally the Sipho- nophora are directly allied to the hy- droid-stocks; but they possess to a much greater extent than the latter the characters of individuals, in consequence of the highly developed poly- morphism o f their polypoid and medusoid appendages. The functions of £he latter seem so inti- mately con- nected and are so essential for the preserva-. • / FIG. 185.—Diagram of a colony of Pliysophorida. /SV, Stem; ETc, ectoderm; En, cntoderm; I'n, Pneumatophor; Sk, nectocalyx beinR budded off; 5, nectocalyx; D, hydrophyllimm; 6f, pono- phore; T, daetylozooid; Sf, tentacle ; P, polyp; O, mouth of the latter ; Nk, battery of nernatocysts. i tion of the entire colony that we may regard each colony of Sipho- * Besides Kolliker, C. Vogt, Huxley and others, compare C. G-egenbaur, " Beobachtuogen liber Siphonophoren," •Zcitschrift fur wixtt. Znol., 1853. 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. London, Swan Sonnenschein & co.
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