664 SILURIAN TRILOBITES OF XEW SOUTH WALES, V., 



The prominence and siibgiobular form of tlie eyes are just as 

 charactei'istic features of E. boivnin<jf'7is'is as is the tuberculation 

 of the glabella. We can only again express our regret at our 

 absolute inability to unravel the identit}^ of De Koninck's 

 Australian trilobites. 



The tuberculation of the glabella is a most marked feature in 

 this trilobite. In an exceptionally well preserved example, the 

 tubercles on the semiglobular anterior portion of the glabella are 

 in three concentric rows around a central one. The first is a 

 circlet round this last, formed of five or six tubercles, the second 

 is a semicircle commencing at the anterior pair at the anterior 

 (third) pair on the glabella neck, and the third, also semicircular, 

 passes round the front bordering the anterior branches of the 

 facial sutures, and is continuous with the marginal tubercles 

 overhanging the axial grooves. 



The hypostome, so far as a mutilated specimen enables us to 

 judge, resembles that of E. mitcheJli. As in the preceding species 

 and in accordance with the generic formula, there are eleven 

 thoracic segments. In the pygidium there is no constant ratio 

 between its length and that of either the cephalon or thorax. 

 In a number of specimens the length appears about equal to the 

 axial length of nine of the thoracic segments. 



Both Mr. A. Brongniart and Mr. Fletcher stated the tubercles 

 of E. puncfafus to be perforate, and the latter so figured them,* 

 but we have not detected this in either E. mifchelli or E. bown- 

 iiigeyisw. In the tuberculation of the central area of the axis of 

 its pygidium, E hownincfensis closely resembles E. j)U7ictatns. 



Loc. and Hor. — Bowning Creek, Parish Bowning, County 

 Harden (J.M.); Limestone Creek, Parish Yass, County King 

 (J.M.); Jones' or Derrengullen Creek, Parish Yass, County King 

 (J.M.); Hatton's Corner, shale below the limestone, Parish Yass, 

 County King; Burrowa Road, near Bowning, Parish Bowning, 

 County Harden. (Coll. Aust. Mus., presented by A. J. Shearsby). 



Lower Trilobite Bed, Bowning Series. Upper Silurian, = 

 ?Wenlock Beds of Great Britain. 



Fletcher, Quart. Journ. Geol. Soc, 1850, vi., p. 403, PI. xxxii., fig.96. 



