. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). ( TUE CTENOPIIOHA. 123. Fia. OH.—Adiiksivk Ckm-s FUOM TkNTACLK. iiV A CtenoI'IIOuk (after Chun). c = mllu'sive cup. m = coutructilc stalk the primary axis is practically wanting, the secondary tentacles arising directly from the bottom of the tentacle-sheath. The ectoderm of the secondary tentacles contains nu- merous cells supposed to be sensory, and also so-called adhesive cells, which in this group replace the nematocysts. They consist of a slender spirally- coiled m
. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). ( TUE CTENOPIIOHA. 123. Fia. OH.—Adiiksivk Ckm-s FUOM TkNTACLK. iiV A CtenoI'IIOuk (after Chun). c = mllu'sive cup. m = coutructilc stalk the primary axis is practically wanting, the secondary tentacles arising directly from the bottom of the tentacle-sheath. The ectoderm of the secondary tentacles contains nu- merous cells supposed to be sensory, and also so-called adhesive cells, which in this group replace the nematocysts. They consist of a slender spirally- coiled muscular fibre (Fig. <)8, m) at- tached at one extremity to the subja- cent tissue and terminating at the other on the under surface of a hemi- spherical cap (c), whose surface is covered by small spherical masses of a sticky secretion. A small animal coming into contact with these caps is held by the adhesive secretion, the muscle-fibre being suf- ficiently elastic to yield to the struggles of the victim and t(» bring it in contact with the general ectoderm by contracting when its struggles cease. The reproductive organs lie in the outer walls of the canals which lie beneath the meridional rows of plates, but apparently are originally derived from the ectoderm. All the Oteuophores are hermaphrodites, the ova being arranged oi. one side of each canal and the spermatozoa on the other, in such a manner that the adjacent sides of any two canuis bear the same kind of sexual cells. A peculiar phenomenon termed Dissogony has been observed in certain forms, consist- ing of the occurrence of two periods of sexual maturity in the life-history of the individual, the reproductive organs ripening first while it is still in a larval stage and again when it has reached its adult form. The main bulk of the body of a Ctenophore is made up by a gelatinous tissue intervening between the endoderm and ectoderm and which may be termed the mesogloea, though it is not improbable that its cellu
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1894
