radiole

Noun

radiole (plural radioles)

1. The spine of a sea urchin.
   • Radioles or spines [...] are the appendages articulating upon the tubercles. The different parts of the spines are the socket by which it is articulated to the tubercles; the lower part of the radiole is called the head, and is separated from the neck, which is usually smooth or finely striated, by...1874, Alexander Agassiz, “Terminology”, in Revision of the Echini (Illustrated Catalogue of the Museum of Comparative Zoölogy, at Harvard College; VII), part IV (Structure and Embryology of the...
   • The radioles of the second size are about 8 millims. in length and 2 millims. in width, very much compressed and flattened, rounded at the end and finely striated longitudinally. They are articulated in a single row to the small tubercles round the edge of the areola, and in their natural attitude...1874 April 9, [Charles] Wyville Thomson, “XXI. On the Echinoidea of the ‘Porcupine’ Deep-sea Dredging-expeditions”, in Philosophical Transactions of the Royal Society of London, volume 164, part II...
2. A heavily ciliated feather-like tentacle occurring in clusters on the crowns of certain tubeworms, especially those of the order Canalipalpata (fan-head worms), used for feeding and respiration.
   • Fabricia bikinii, n. sp. [...] The tentacular crown is composed of three pairs of symmetrical radioles; in addition there are shorter, entire, paired filamentous processes, or palpi, at the ventral end of the crown [...]. Each radiole has 6 to 8 pairs of slender filaments that arise along the basal...1954, Olga Hartman, “Systematic Descriptions”, in Marine Annelids from the Northern Marshall Islands: Bikini and nearby Atolls, Marshall Islands (Geological Survey Professional Paper; 260-Q)...
   • The anterior segments of sabellid and serpulid worms are modified in two important ways: the head has a crown of pinnate radioles arranged in two spirals or semicircles above the mouth, and some of the anterior segments form a thoracic region [...]. In the Serpulidae, one (sometimes two) of the...1990, Vernon A. Harris, “Tube-dwelling Worms (Annelida – Polychaeta)”, in Sessile Animals of the Sea Shore, London; New York, N.Y.: Chapman and Hall, →ISBN, section 7.2 (Structures Related to a...