312 THE SILURIAN TRILOBITES OF NEW SOUTH WALES, 



near Kilmore, Victoria, a species under the name of Forbesia 

 euryceps, which is peculiar from the great width of the cephalic- 

 shield, widely divergent genal angles, and the long spines attached 

 thereto. 



Prof, de Koninck referred three small pygidia from Yarralumla, 

 N. S. Wales, to the British Proetus Stokesii, Murchison,* but the 

 only distinctive character which can be seized on is the presence 

 of six or seven axis rings. These tails probably belong to one or 

 other of the forms described later, and not to P. Stokesii at all. 



The late Mr. F. Ratte described! a Trilobite from Bowning, 

 referring it to Proetus ascanius, Corda, as figured by Barrande. 

 This form will be discussed later on. 



On two separate occasions a Proetus and a Cyphaspis have been 

 described by one of us, the former as P. bowning 'ensis, t from the 

 Lower Trilobite Bed at Bowning, the latter as C. boivningensis,§ 

 from the same locality and similar horizon. These will be forth- 

 with re-described. 



This, so far as we know, is an epitome of all that has been 

 written on the Proetidse of Australian Silurian rocks. 



Genus Proetus, Steininger, 1831. 

 (Mem. Soc. Geol. France, I., p. 355.) 



The groups which have been proposed within the wider generic 

 term Proetus are the following : — 



1. Photon, Barrande, 1846. Pygidium with the pleurae pro- 



duced into spines, forming a fimbriated circumference. 



2. Forbesia, McCoy, 1846. Genal angles produced into long 



spines ; pleurse of the pygidium segmented ; glabella 

 furrows present ; and large tubercles terminating the 

 neck-furrow. 



* Foss. Pal. Nouv.-Galles du Sud, 1876, Pt. 1, p. 56. 



t Proc. Linn. Soc. N. S. Wales, I. (2), p. 1066, t. 15, f. 1-4. 



X Proc. Linn. Soc. N. S. Wales, 1887, II. (2), Pt. 3, p. 439, t. 16, f. 4-6. 



§ Proc. Linn. Soc. N. S. Wales, 18S7, II. (2), Pt. 3, p. 438, t. 16, f. 3. 



