42 
Horizon and Localities . — Several speeimens have been found at Yarra- 
lumla in a grey argillaceous limestone, which most probably corresponds to 
the 'VYenlock Limestone. They are there associated with Calymene Blumen- 
hachii, Ah Brong. 
Genus — CROMU S, Barrande. 
1. Ceomtjs eoiiemicus (?) J. Barrande. 
CromilS boheniicus, Barrande, Syst. Sil. Bolieme, 1852, I, p. 828, pi. 43, fig. 15-17. 
The head is snh-semicircnlar. The glabella is elongate, slightly arched, 
and is widest a little behind the anterior end ; on either side there are four 
narrow glabella furrows, straight and nearly equally arranged between the 
base and the point of greatest width ; it has a great number of granulations, 
some of Avhich are larger than the others. The fixed cheek is separated from 
the glabella by a well-marked furrow ; it is sub -triangular, and occupies the 
entire width of the corresponding thoracic lobe. The genal angle is rounded. 
I have not had the opportunity of examining either the eye or the 
thorax. 
The pygidium, sub-triangular in form, is a little broader than long, and 
is strongly arched transversely. The axis is made up of twenty-five to thirty 
segments, and is only about half the width of each of the lateral lobes, above 
which it scarcely projects ; some of the anterior rings are well marked 
throughout, while the majority of the others are discontinuous towards the 
middle of the axis, and on this q)ortion are ornamented with several small 
granulations. Each of the lateral lobes is made up of eleven or twelve ribs, 
the direction of which approximates to that of the axis in proportion as their 
point of origin is further from the thorax ; they are a little broader on the 
edges of the lobes than on the other side, and terminate in a small angular 
projection which gives a dentate appearance to the outline of the pygidium. 
Observations . — All the characters I have just mentioned are shown on 
the two specimens I refer to the species described by Barrande, and found 
by him in Bohemia. Although they may be very similar to those described 
by the learned Erench palaeontologist, I have some doubt as to the identity of 
the Australian and Bohemian specimens, because the glabella apjiears to me 
to be too inflated. In the last si^ecies the furrov^s that separate the ribs are 
