178 THE SILURIAN TRILOBITES OF NEW SOUTH WALES. 



EXPLANATION OF PLATES. 



Plate vi. 



Cyphaspis yassensls, Eth.,JiL, and Mitchell . 



Fig. 1. — Cephalic-shield; a large specimen showing auditory organs ( x 3). 



Fig. la. — Pygidium, a large specimen ( x 3). 



Fig. 1^. — Pygidium and two segments of thorax attached ( x 3). 



Fig. Ic. —Cephalic-shield without free cheeks ; a well preserved specimen 



showing no signs of glabellar furrows. 

 Fig. \d. — Free cheek (nat. size). 



Cyphaspis rotunda, Eth.,Jil., and Mitchell . 



Fig. 2. — An almost complete specimen slightly contorted and completely 



decorticated ( x 6). 

 Fig. 2a. — The same restored ( x 6). 

 Fig. 2&. — Side view of same ( x 6). 



Cyphaspis bownixgensis, Mitchell. 



Fig. 3. — Young specimen somewhat contorted and one free cheek missing 



(x3). 

 Fig. 3a. — Cephalic-shield and six segments of the thorax, with dorsal spine 



on the sixth segment, and showing the granular ornamentation 



distinctly ( x 2). 

 Fig. 36. — Side view of same. 

 Fig. 3c. — Side view of Fig. 3. 



Fig. M. — Portion of thorax, with pygidium and dorsal spine complete. 

 Fig. 3e. — Portion of thorax and spine ( x 3). 

 Fig. 3/-A. — Cephalic-shields showing variations ; oh-j are from the Middle 



Trilobite bed and are decorticated and contorted ; 3[/ shows a 



very wide border, and like Zh-j indicative of glabellar furrows 



( X 3). 



Plate vii. 



Fig. 3i-/i'. — (Vide explanation of 2>f-h.) 



Cyphaspis Horaxi, Eth.,fil., and Mitchell. 



Fig. 4. — Cephalic-shield with one free cheek missing, showing genal spine 

 and very faint serration of anterior edge ( x 3). 



Fig. 4a. — Thorax and pygidium complete and posterior portion of cephalic- 

 shield inverted, decorticated ( x 4). 



Fig. 46. — Portion of a thorax and pygidium of a smaller specimen than 4a 

 (X 6). 



Fig. 4c. — A very well preserved cephalic-shield without the free cheeks, 

 showing the ornamentation ( x 6). 



