668 SILURIAN TRILOBITES OF NEW SOUTH WALES, V., 



strongly thickened; axial grooves pronounced; side-lobes flat 

 between the axial grooves and fulcra, thence steeply deflected. 



Pygidium triangular, wider than long and longer than the 

 thorax, surface apparently smooth; axis wide anteriorly, but the 

 first annulation narrower than the last of the thoracic axis; each 

 of the first three annulations contract somewhat rapidly, and 

 thence the contraction is gradual to the blunt termination, rings 

 approximately thirty-six, of which the first three are continuous, 

 anterior half prominent and arched, but becomes decreasingly so 

 posteriorly; medial tubercles inconspicuous; pleura? normally of 

 thirteen pairs of annulations; each pleura much wider than the 

 greatest width of the axis; only the anterior pair have distinct 

 fulcra, the others more or less slope steeply from the axial grooves 

 downwards and increasingly backwards, the last being parallel 

 with the axis terminal; anterior pair very strongly faceted; axial 

 grooves distinct anteriorly, but becoming quite indistinct pos- 

 teriorly. 



06.s\ — This is the largest of the Australian Encrinuri known 

 to us, the type-specimen having a length of two and a half 

 inches, of which the tail accounts for one inch. In several 

 features, as for instance the general form of the complete fossil, 

 glabella, and the anterior portion of the pygidial axis, this species 

 resembles E. mitchelli. The much greater relative size of the 

 pygidium, greater number of segments in the pleurae and axis of 

 the pygidium, the more prominent eyes, and wrinkled nature of 

 the cephalic tubercles, easily separates it from that species. It 

 is so evidently distinct from all other species that we deem it 

 quite unnecessary to note the differences. 



i^amed after Mr. Robert Etheridge, J.P,, Curator of the Austra- 

 lian Museum, Sydney, IST. S. Wales, as a small token of the ap- 

 preciation in which he is held as a friend and collaborator by me 

 (J.M.). The type-specimen was found by Mr. Etheridge during 

 one of our geological excursions. 



Loc. cmd Hor. — -Yarralumla Plains (Limestone Plains), Parish 

 of Narrabundah, County Murray (Etheridge and Mitchell). 

 Gurnett's Farm, Parish Bowning, County Harden, (J. M.). ?Up. Sil. 



