Regular sea-urchins, as a rule, prepare and process their food as pellets in their buccal cavity before ingesting them. This is obtained through the synergistic interaction of the five teeth with five fleshy protuberances (paradental tongues) which extend into the oral cavity and work like tongues. Each of these structures consists of two anatomically distinct parts: the outer component is a deep pouch of the terminal tract of the pharynx and shows a histological organization similar to that usually shown by the pharyngeal wall itself. The deeper component (paradental axis) is represented by a supporting rod and shows a peculiar histological structure, which consists of glycogen containing vesiculate cells mixed to slim muscle fibres and held together by a thin fibrillar stroma. The paradental axes are very problematic structures in terms of comparative anatomy and phylogenetic aspects. Their microscopic and submicroscopic organization is unusual for an echinoderm and recalls that of different types of chordoid organs commonly found in other invertebrates (Protostomata and Deuterostomata).
Atypical chordoid structures in the Aristotle's lantern of regular echinoids. / F. Bonasoro, M.D. Candia Carnevali. - In: ACTA ZOOLOGICA. - ISSN 0001-7272. - 75:2(1994), pp. 89-100.
|Titolo:||Atypical chordoid structures in the Aristotle's lantern of regular echinoids.|
BONASORO, FRANCESCO (Primo)
CANDIA, MARIA DANIELA (Ultimo)
|Parole Chiave:||Chordoid structures|
|Settore Scientifico Disciplinare:||Settore BIO/05 - Zoologia|
|Data di pubblicazione:||1994|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1111/j.1463-6395.1994.tb01114.x|
|Appare nelle tipologie:||01 - Articolo su periodico|