and body wall in echinoids and holothuroids. The ‘BD different’ pattern of primary brachioles in pentaradiate glyptocystitoid Rhombifera results from subterminal branching of the ambulacra. lacra in other groups of Eleutherozoa (Hotchkiss, 1995, 1998a) so the plane of symmetry 2–1–2 can be, holothurians (fig. Explanation: (D–V) bilateral plane of symmetry; (DS) dorsal side of the body (bivium); (LS) left side of the body; (RS) right side of the body; (VS) ventral side of the body (trivium); (R') holothurian radius; (amhv) antimesenterial haemal vessel; (ap) tube feet; (apa) tube feet ampulae; (api) ascending part of intestine; (d) dermis; (enc) epineural canal; (ep) epidermis; (fdpi) first descending part of intestine; (g) gonada; (gd) gonoduct; (hmc) hypoo neural canal; (lm) longitudinal muscle band; (mes) mesenterium; (mhv) mesenterial haemal vessel; (nc) radial ectoneural and hyponeural nerve cords; (rm) ring muscles; (rc) radial water vascular (ambulacral) canal; (sdpi) second descending part of intess tine; (wl) water lung. (1) The longitudinal axis mouth–anus in most extant, holothurians is aligned parallel rather than perpendic, in the body plan of the modern echinoderms, the morphogenetic, archetype of all echinoderms should include the bilaterally asym, Sea Cucumbers Symmetry (Echinodermata: Holothuroidea), Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 14, pp. (1946); (g) from Ivanov and Strelkov (1949); (h) from MacBride (1906); (i) from Heding (1935). On the positive side, it is ob­ viously necessary and desirable to extend and expand the inquiry; but one regrets that already we are beginning to talk past, lose track of, and even ignore each other as we carve out individual interests. deepening understanding of the mechanisms of ontogeny, in particular, of the latent potencies, lead to the conclu, dants of the character lost even in embryos, provided that, the morphogenetic mechanisms responsible for the devel, opment of such a character are retained in one form or, Radii of other echinoderms topologically corre, spond to both primary tentacles and proper radii of, holothurians. Высказано предположение что вогнутые склериты чашеобразной формы c тремя-пятью лучами встречающиеся в семействе Laetmogonidae (отряд Elasipodida) имеют педоморфное происхождение и представляют разросшиеся начальные стадии колес летмогонидного типа, а от этих склеритов, в свою очередь, могли произойти изогнутые крестообразные склериты свойственные семействам Elpidiidae и Psychropotidae. But the body symmetry of sea cucumber is bilateral, i.e., it has a well defined dorsal and ventral side. Other examples of Lovén's Law occur in Diploporita, Ophiuroidea, Edrioasteroidea, Edrioblastoidea, Holothuroidea, Ophiocistioidea, and Bothriocidaris . However, the present approach, which follows the principles of constructional morphology, supports former views that the holothurian predecessor must have been echinoid-like. Bather’s theory, ) water vascular (ambulacral) podia canal; (. ) Sea Cucumbers Symmetry (Echinodermata: Holothuroidea) December 2014; Paleontological Journal 48(12):1215-1236; DOI: 10.1134/S0031030114120107. Get the unbiased info you need to find the right school. Особенно ярко педоморфные черты проявляются в строении мелких интерстициальных форм. 6a) and even planktonic lifestyle. In Scoliorhapis spp., Taeniogyrus havelockensis, Kolostoneura novaezealandiae, Psamm mothuria ganapatii (Taeniogyrinae, Chiridotidae), Lep tosynapta minuta, Rhabdomolgus ruber (Synaptidae) the intestine is suspended only by mediodorsal mesenn tery along almost its entire length (, Our recent expedition to Chukchi Sea (Vrangel and Herald islands area) has collected a number of Echinodermata species including sea urchins, ophiuroids, holoturians and sea stars. ambulacral canals that carry out a locomotor function. (3) The availability of larva, specific to holothurians, an auricularia. 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