spicule

Webster's Dictionary (1913)

Origin: L. 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.

☞ 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.

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.

Webster’s Revised Unabridged Dictionary (1913), from GCIDE 0.54