440 ON SOME NEW TRILOBITES PROM BOWNING, N.S.W. 



the medial one is not narrower than the adjoining rib. The 

 compressed state, therefore, of this rib in the specimen described, 

 may be only characteristic of young specimens. 



In conclusion I have to express my obligations and thanks to 

 Mr. E, Etheridge, F.G.S,, who has kindly helped me with sugges- 

 tions and advice. 



EXPLANATION OF PLATE. 



Fig. 1. — Brontcus longispinifex — Pj'gidium and 6 segments of thoi-ax ( x3). 

 Fig. 2.— ,, „ Head and one free cheek. (Nat. size). 



Fig. 3. — Cijphaspls Boivningensis { x 2). 

 Fig. 4. — Proetus Boivniiigensis—^ygid'mm and head, the latter turned back 



on the thorax. (Nat. size.) 

 Figs. 5 & 6. — Proetus Boioningensis— Another head and pygidiuni. (Nat. 



size.) 



