[Neal Robbins]

Olenoides nevadensis was a species of trilobites that lived during the Cambrian period. Fossils of this species have been found in the Marjum and Wheeler formations of Utah. Olenoides nevadensis was typically about 50 mm. long. This species had needle-like axial and pygidial spines (ones protruding from the pygidium, i.e. the back portion).
The taxonomy of Olenoides nevadensis is:

Kingdom: Animalia
Phylum: Arthropoda
Class: Trilobita
Order: Corynexochida
Suborder: Corynexochina
Family: Dorypygidae
Genus: Olenoides
Species: Olenoides nevadensis

[Note - Another species of the genus Olenoides is Olenoides superbus. Fossils of it have been found in the Marjum Formation of Millard County, Utah.]

Neal Robbins

P.S. As is mentioned in the taxonomy, Olenoides is of the order Corynexochida. As with other trilobites, those of the Corynexochida order have bodies that are divided into three main portions:

(1) Cephalon (head) - The glabella (middle part of cephalon) is elongated. The sides are often concave. Furrows are sometimes effaced. When they are not effaced, they have a splayed arrangement. The anterior pairs are oriented in a forward direction. Back pairs are pointed sharply backwards. The furrows are sometimes pit-like. Cranidial borders are frequently ledge-like. The hypostome is contermint; in derived forms it usually is impendent. Eyes are large; in some cases they are gently arcuate.
[Note - The hypostome is a piece of exoskeleton on the venter (underside) of the cephalon; it is thought to be a part of the mouth. If the hypostome is contermint, it is attached to the anterior doublure via the suture.]
The doublure is a shell continuation under the trilobite. It is usually in the form of a ventral cephalic and/or pygidial rim. The suture is a linear break in the exoskeleton. The parts along it typically separate during molting.

(2) Thorax (middle portion) - There are usually 7-8 segments, though the range is 2-12. Pleural tips are often spinose.
[Note - Pleural refers to pleurae (plural of pleura). The pleura is the lateral part of the thoraxic segment or lateral (non-axial) part of pygidium.

(3) Pygidium (back portion) - It is generally large and sometimes spinose. The pygidium is isopygous or subisopygous.
[Note - Isopygous means that the cephalon and the pygidium are similar in shape. Subisopygous means that the pygidium is large, but is smaller than the cephalon (head).