madreporite


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madreporite

the porous opening to the hydrocoel in ECHINODERMS.
References in periodicals archive ?
Seawater is able to enter through madreporite which is a spinous skeletal plate that presents on aboral surface of S.
(a) aboral view, R = 66 mm; A: madreporite; B: spine (blunted); C: superomarginal plate; (b) oral view, r = 26 mm; D: actinal intermediate areas, with numerous pigmentation lacking suboral spines; E: furrow spines; F: subambulacral spines; G: inferomarginal plate; H: mouth; I: ambulacral groove; J: adambulacral border.
In addition, an understanding of the arrangement of the primary skeletal structures during the early post-metamorphic stages of Asteroidea allows identification of the true homologies and ontogenetic patterns inferred from evolutionary models (the Ocular Plate Rule and the Madreporite Mode Appearance) (Mooi and David, 2000; Gale, 2011).
Formation of the madreporite is observed in juveniles at 88 days after fertilization (Fig.
The uniqueness of the madreporite creates an asymmetry within the
madreporite in the apical system, even the regular echinoids are
Initial orientation was standardized relative to the madreporite to minimize potential directionality bias (Polls and Gonor, 1975).
During each 25-min trial, the position of the sea star (determined using the madreporite as a reference) was recorded by eye every 30 s.
The madreporite is attached to a ciliated "stone canal" that connects through a series of passages to the animal's fluid-filled appendages, the tube feet.
In addition, the madreporite may contribute water to the water vascular system and perivisceral coelom (Ferguson, 1989, 1990b).
One month later (mid-June), the young starfish possessed a well-developed buccal cavity, stomach, and pyloric caeca, which were easily observed across the transparent body wall on the oral surface [ILLUSTRATION FOR FIGURE 9L OMITTED] with the madreporite and anus on the aboral surface.
It is generally assumed, for example, that the madreporite admits seawater into the system, and that ciliary pumping by the stone canal connected to it forces the seawater taken in to flow out to the tube feet where it replenishes fluid losses due to their activity.