47 
Relations and Differences . — I know Init two Silurian species of Rron- 
ieus in wliicli the pygiclinm is siirrounclecl hy projections, viz.' — R. thysano- 
l^eltis and. R. clementiniis, Barrande. It differs from the first in the nnmher 
of projections, and from the second in the shape and small length of these, 
and from both in its median rib, which is simple, while in its congeners it is 
bifurcated. 
Horizon and Locality . — Bound at Bock Blat Creek in an ochreons, 
rather compact argillaceous rock. 
Genus — IIABBES, Goldfuss. 
IIarpes ungula, Sternherej. 
Trilobite Sliugula, Yon Sternberg, 1833, Verbandl. Gesells. Yaterl. Mus. Bolim., p. 52, pi. 2, 
fig. ]. 
Harpes ,, Burmeister, 1813, Organ. Trilob., p. 88. 
,, tenuipunctatus (.^) J. Barrande, 181G, Not. Prelim, sur les Trilob., p. 55. 
,, lingula, Hawle and Corda, 1847, Prodr. einer Mon. Bdbm. Trilob., p. 163, pi. 7, 
fig. 38. 
„ concamis, Idem, id., ihid., p. 163. 
,, SCulptus, Idem, id., ihid., p. 163. 
,, ungula, J. Barrande, 1852, Syst. Sil. Bohome, I,p.3l7, pi. 8, fig. 2-6, and pi. 9, fig. 1-6. 
The characters of the single specimen of Harpes that has been 
submitted to me, consisting of an almost complete head, agree so exactly 
with the description and figures that Barrande has given of H. ungula, 
Sternberg, that I think I am not wrong in referring it to this species. I will 
not, therefore, enter into greater detail concerning it, details that will he found 
thoroughly descriljed in the work of the eminent Erench pala3ontologist 
I have just mentioned. I will only say that the head in question belongs to a 
young individual, and has a length of only three millimetres. 
Horizon and Localities . — In Bohemia this species belongs to the lime- 
stone of Barrande’s Etage E., and consequently, to the Upper Silurian. It is 
there found in a large number of localities. In Australia it has been collected 
at Borec Cave in a mottled limestone, associated with Rronteus RartsoM. 
