246 TRILOBITA CHAP. 
projection nearly as far as the posterior end of the thorax. The 
glabella is convex and does not reach the front margin. The 
cheeks are less convex than the glabella, and bear eyes which 
usually consist of two or three lenses. An eye-line connects 
the eye with the anterior part of the glabella. A suture is stated 
to occur at the external margin of the flat border. The thorax 
consists of from twenty-five to twenty-nine segments; its axis 1s 
narrow, and the pleurae are long and grooved. The pygidium is 
very small, and consists of three or four segments. Ordovician 
to Devonian. Genus: Harpes. 
Fam. 5. Paradoxidae (Figs. 147, 148, 149).—The cephalic 
shield is large, and bears long genal spines. The glabella is more 
(p ae 
) 
_, 
i 
i 
i) 
il 
\ 
TR 
WCC 
ma 
mil 
sul 
pS 
ZZ 
SS 
Ny 
EY 
Fic. 147.—Paradoxides bohemicus, Fic. 148.—-Holmia kjerulfi, Linnars. 
Barr. x 4. Middle Cambrian. x 1. Lower Cambrian. (After 
(After Zittel. ) Holm.) 
or less swollen in front. The facial sutures appear to be absent in 
some genera, and when present extend from the posterior to the 
anterior margin. The palpebral lobes are long, and often more 
or less semicircular or kidney-shaped. The thorax is long, and 
consists of from sixteen to twenty segments with their pleurae 
produced into spines. The pygidium is very small, and plate-like, 
