Note 459 — Chapter IX · ON CONCRETIONS, SPICULES, AND SPICULAR SKELETONS
Reading edition
For very numerous illustrations of the triradiate and quadriradiate spicules of the calcareous sponges, see (int. al.), papers by Dendy (Q. J. M. S. XXXV, 1893), Minchin (P. Z. S. 1904), Jenkin (P. Z. S. 1908), etc.