CRUSTACEA. 
83 
constricted at its base as in Conolichas. The third pair of lateral lobes which 
is usually present in typical species of Hoplolichas, is almost if not quite obso¬ 
lete in L. hylcBus, and the species bears the same relation to the Silurian forms 
of Hoplolichas as L. Eriopis does to the Silurian s|)ecies of Conolichas (See 
observations under the description of L. Eriopis.) 
Distribution. Upper Helderberg group. In the limestone, Province of Ontario. 
[s.-G.] A ROES, Goldfuss. 1839. 
Lichas (Arges) contuses, n. sp. 
PLATE XIX B, FIGS. 3-6. 
Cephalon broadly semi-oval in outline. Surface sub-equally trilobate, evenly 
convex. 
Glabella with an elongate frontal lobe, having a width equal to that of each 
of the lateral lobes, and bounded by furrows which are parallel for three- 
fourths their length, diverging near the frontal margin, thus greatly increas¬ 
ing the width of the lobe upon the anterior border. First and second pair of 
lateral lobes coalesced into a single pair of relatively short, obliquely pyri¬ 
form lobes, terminating posteriorly sooner than the frontal lobe. The third 
pair of lateral lobes are obsolete or represented only by tubercles in the 
occipital furrow. 
The fixed portion of the cheeks is convex behind the eye-nodes, and abruptly 
deflected to the occipital furrow. Occipital furrow broad and deep upon 
the axial line at the posterior termination of the frontal lobe, narrowing 
upon the cheeks and bending forward to very near the ocular node; occipital 
ring axially convex, relatively narrow, making a marked anterior curve upon 
the sides as it turns toward the presumably very narrow and slender free 
cheeks. Frontal border narrow and thickened, with a strong marginal 
sulcus. Surface covered with closely set and evenly distributed tubercles. 
The remaining parts of the animal are unknown. 
Dimensions. Two specimens of the intra-sutural portions of the cephalon 
have a length of 7 mm., and a width of 11 mm. 
