TRILOBITES, &c. 
= nrp® e@ Oe coo 
Genus Catymene. JSrongniert. 
*~ 
Tue name of this genus is derived from a Greek 
word which signifies obscure or concealed. The fossil 
animals included by it are characterized as having 
contractile bodies; the buckler as bearing many tu- 
bercles or folds—the epee ks as being oculiferous, 
and the abdomen and tail as being composed of from 
twelve to fourteen articulations or joints, without 
any membranaceous expansion. The Calymenes in 
‘thickness are nearly semicylindrical, and the buck- 
’ ler in front presents a chaperon or upper lip more or 
less raised. In perfect specimens, there is a small 
furrow which seems to indicate a separundn between 
the > upper and under parts of this kind of lip. The 
eyes are always raised, and frequently present the re- 
markable structure observable in many of the crusta- , 
cea; but as this part is generally very prentinent, mae 
reticulations of the eye are commonly worn off or 
jured. a : | 
Professor Brongniart places but little confidence 
in any of the generic characters above enumerated, 
except the number of articulations of the abdomen: 
