Mem. Nat. Mus. Vict., XI, 1939. 
THE SILURIAN TRILOBITE LICHAS AUSTRALIS. 
By Edmund D. Gill, B.A., B.D. 
(Plate V.) 
In the year 1876, McCoy (3) described the Trilobite LicJias 
australis from two distinct but incomplete cephala from the 
“Junction of Woori Yallock and Yarra (Stewart’s Station).” 
In the succeeding 63 years occasional cephala of this species 
have been collected, and also pygidia, which, because no other 
species of Victorian Lichas has been known, have been 
surmised to belong to Lichas australis. A complete carapace 
from Syme’s Quarry, Killara, presented by Mrs. Robert 
Bowie, of Killara, to the National Museum, has now proved 
that surmise to be correct, and has made possible a fuU 
description of the species. 
Order OPISTHOPARIA Beecher 
Eamily LICHADIDAE Corda 
Genus LICHAS Dahnan 
McCoy’s description is as follows: 
“Width across glabella and middle of anterior lateral lobes, fths of 
the length of the head, including neck-segment; middle portion of 
glabella tumid, broadly rounded in front, rather narrowed in the middle 
by the regular inward curvature of the anterior segmental furrows; 
anterior segmental lobes ovate, tumid ; cheeks very tumid in an oblique 
line from the small eyes to the neck-segment, which is strongly marked 
and separated from base of glabella by a wide sulcus ; surface covered 
by coarse unequal granulation of conical spinose tubercles ; three 
conspicuous tubercles in sulcus at base of glabella. Length of head, 5 
lines.” 
A supplementary description based on the complete 
carapace is given below. 
Carapace ovate in outline, thin, tuberculate. Large cephalon and pygidium. 
Cephalon semi-circular. Neck-segment conspicuously wider than base 
of glabella. Free cheeks diminutive, apparently bearing genal spines. Eyes 
small and set on pedicels which contact with the antero-lateral corners of 
the fixed cheeks. Visual surface unknown. Pedicels high, more or less 
rounded in cross-section, tuberculate. When the cephalon is viewed from 
above, the pedicels are seen projecting at an angle of 45 degrees with the 
glabella. The posterior margin of the cephalon forms a straight line. 
Thorax of eleven segments. A little longer than pygidium. Axial lobe 
wide, strongly arched. Pleura flat, tuberculate, produced into long spines. 
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