Return

Olenellus

OLENELLUS A trilobite with an exoskeleton of subovoidal form, characterized by a broad cephalon and a small pygidium. The glabella, the raised portion at the center of the cephalon, is elongate and almost cylindrical in shape, with a rounded frontal lobe and three pairs of lateral furrows and extends as far as the anterior border of the cephalon; the palpebral lobes, above the eyes, are elongate. The genal spines, positioned at the posterior extremities of the cephalon, are short but pronounced. The thorax, as is charactheristic of some Olenellidae, is divided into two sections: the anterior part of the thorax (opisthothorax) contains a variable number of segments (about 30) bearing somewhat rudimentary pleurae, with the first of these posterior segments carrying a long, central, retroflex spine. The pygidium is very small. © 1986 by Arnaldo Mondadori, Milan .

8cm