Starfish to starfish by the French zoologist de Blainville in 1830. It is derived from the Greek "aster", ἀστήρ (a star) and the Greek "eidos", εἶδος (form, likeness, appearance). The class Asteroidea belongs to the phylum Echinodermata. As well as the starfish, the echinoderms include sea urchins, sand dollars, brittle and basket stars, sea cucumbers and crinoids. The larvae of echinoderms have bilateral symmetry, but during metamorphosis this is replaced with radial symmetry, typically pentameric. Adult echinoderms are characterized by having a water vascular system with external tube feet and a calcareous endoskeleton consisting of ossicles connected by a mesh of
Gracile Atlantic spiny rat is inappropriate because the word has nothing to do with the meaning or etymology of the Latin "gratiosus". A rival name, "graceful spiny-rat", is no better justified; ""gratiosus"" specifically means either "enjoying favour, favoured, beloved", or "showing favour, complaisant" "a favourite", or at best "gracious", not "graceful". No authority to date has proposed a better option than using the species name, "Trinomys gratiosus" in English. Gracile Atlantic spiny rat Trinomys gratiosus is a species in the mainly South American family Echimyidae, the spiny rats; it occurs in southeast Brazil from the south bank of the River Doce, Espirito Sante, southward