• The outer layer is known technically as the ectoderm, the inner layer as the endoderm (or gastroderm). (wikipedia.org)
  • Between ectoderm and endoderm is a supporting layer of structureless gelatinous substance termed mesoglea, secreted by the cell layers of the body wall. (wikipedia.org)
  • The mesoglea can be thinner than the endoderm or ectoderm or comprise the bulk of the body as in larger jellyfish. (wikipedia.org)
  • Similarly, circularly disposed muscular fibrils formed from the endoderm permit tentacles to be protract or thrust out once they are contracted. (wikipedia.org)
  • The intimate connection between the plexus and endoderm, and its less intimate connection with ectoderm. (biologists.com)
  • The oral end contains the mouth, and is surrounded by a circlet of tentacles. (wikipedia.org)
  • The sac-like body built up in this way is attached usually to some firm object by its blind end, and bears at the upper end the mouth which is surrounded by a circle of tentacles which resemble glove fingers. (wikipedia.org)
  • Longitudinal muscular fibrils formed from the cells of the ectoderm allow tentacles to contract when conveying the food to the mouth. (wikipedia.org)
  • We can distinguish therefore in the body of a polyp the column, circular or oval in section, forming the trunk, resting on a base or foot and surmounted by the crown of tentacles, which enclose an area termed the peristome, in the centre of which again is the mouth. (wikipedia.org)
  • As a rule there is no other opening to the body except the mouth, but in some cases excretory pores are known to occur in the foot, and pores may occur at the tips of the tentacles. (wikipedia.org)
  • A well developed bud bears its own mouth, hypostome and tentacles. (biologydiscussion.com)
  • The anatomy of Hydra is rather simple: this is basically a bilayered tube that shows an apical-basal polarity, with at one extremity a head region that includes a mouth/anus opening and a ring of tentacles to actively catch the food (Hydra are carnivorous), and at the other extremity a basal disc. (unige.ch)
  • When it is undisturbed, its body remains extended with tentacles spread out and shows expansions and contraction without any apparent reason. (biologydiscussion.com)
  • Polyps extend their tentacles, particularly at night, containing coiled stinging nettle-like cells or nematocysts which pierce and poison and firmly hold living prey paralysing or killing them. (wikipedia.org)
  • The tentacles are organs which serve both for the tactile sense and for the capture of food. (wikipedia.org)