"A. Colony of Pennatula phosphorea from the metarachidial aspect. p, The peduncle. B, Section of the rachis bearing a single pinna. a, Axis; b, metarachidial; c, prorachidial; d, pararachidial stem canals." — The Encyclopedia Britannica, 1910

Pennatula Phosphorea

"A. Colony of Pennatula phosphorea from the metarachidial aspect. p, The peduncle. B, Section of the…