Spicule
Spicule , noun
[Latin spiculum a little point, a dart.]
1.
A minute, slender granule, or point.
2.
(Botany) Same as Spicula.
3.
(Zoology) Any small calcareous or siliceous body found in the tissues of various invertebrate animals, especially in sponges and in most Alcyonaria.
Description of the Illustration:
a Acerate; b Tricurvate, or Bowshaped; c d Hamate; e Broomshaped; f Scepterellate; g Spinispirulate; h Inequi-anchorate; i Sexradiate; j A Trichite Sheaf; k Six-rayed Capitate; l Rosette of Esperia; m Equi-anchorate.
Spicules vary exceedingly in size and shape, and some of those found in siliceous sponges are very complex in structure and elegant in form. They are of great use in classification.