632 ARTHROPODA SUB-KINGDOM VII. 
lateral margins separately. Eyes crescentic. Thorax of ten segments, with ridged pleura. 
Pygidium longer than cephalon or thorax ; axis 
very short, with radiating furrows extending 
from it across the broad limb toward the margin; 
doublure very wide; margin generally entire. 
Ordovician to Devonian. 
This comprises the single genus Bronteus, 
mere Goldfuss (Figs. 1264, 1288, H, 1310). Ordo- 
Frc. 1310. vician to Devonian; Europe and North 
Cephalon of Bronteus palifer, Beyr. Devonian America. Most abundant in the Silurian and 
(Et. F); Konieprus, Bohemia (after Barrande). Devonian of Bohemia. 

Family 6. Lichadidae.  Barrande. 
Dorsal shield generally large and flat, with granulated test. Cephalon small, not 
more than one-fourth the entire length ; genal angles spiniform. Free cheeks separate ; 
sutures extending from the posterior margin obliquely inward to the eyes, and then almost 
directly forward, cutting the margin separately.  Glabella broad, with a large, often 
tumid central lobe, and from one to three side lobes. Eyes not large. Thorax with nine 
or ten segments, and grooved and falcate pleura. Pygidium large, flat, commonly with 
toothed or notched margin corresponding to the pleural grooves; doublure very broad. 
Ordovician to Devonian. 
Most of the forms of this family are above the average size of Trilobites, and 
several species are among the largest of the class. 
They are all thin-shelled, and so loosely articu- 
lated that entire specimens are extremely rare. 
Lichas, Dalman s. str. (Figs. 1262, 1311). 
Anterior lobe of the glabella dominating the 
other lobes, and continuous with the axis; 
lateral lobes reniform and small. Ordovician 
and Silurian ; Europe and North America. EAN ISS 
Sub-genera: Arges, Goldf. (Fig. 1312). Lateral Tok 
lobes of glabella strongly defined, nearly as large 

as the central one, and divided transversely by a : : ei ABTS: Fig. 1312 
: R =) ee SARL SE eae Lichas laciniatus 32 
furrow ; lobes and neck ring often spiniferous; wopip. Silurian: Arges Sarmatue teen 
pygidium with dentate margin and spiniform Sweden (after fuss. Devonian; Ger- 
é * : - Angelin). many (after Beyrich). 
pleural extensions. Silurian and Devonian. 
Dicranogmus, Corda (Fig. 1313). Glabella divided by two longitudinal and one 
transverse furrow into angular lobes; pygidium with annulated axis; limb with a 
few short denticula- 
tions. Silurian. 
\ ( Conolichas, Dames 
(Fig. 1314). Glabella 
haying one large pro- 
truding central, and 
two prominent lateral 
lobes, with sometimes 
Fia. 1313. two smaller basal 
Dieranogmus a aes S, “dovici 
ptyonurus, Hall Fra. 1314. Fic. 1315. lobes. Ordovician to 
and Clarke.  Sil- Conolichas Schmidti, Daines. Ceratolichas gryps, Hall Devonian. 
urian; New | Ordovician; Germany (after and Clarke. Devonian; New = yet: 
York. Dames). ; York (after Hall and Clarke). Ceratolichas, Hall 
and Clarke (Fig. 
1315). Central lobe arched, tumid, with smaller side lobes ; central lobe and occipital 
ring with long curved spines. Devonian ; North America. 

