BY R. ETII BRIDGE, JUNR., AND JOHN MITCHELL. 
We do not notice incidental references to other localities, when 
unaccompanied by descriptions, nor catalogue names in the same 
category. 
The Tasmanian forms are at present undescribed. 
The Phacopidye is represented throughout Australian Silurian 
rocks, so far as we can ascertain with certainty, by two genera 
only — Phacops, Emmrich, and Hausmannia, Hall and Clarke. 
During our researches we have not met with any Trilobites that 
could be referred to either of the following : — Acaste, Goldfuss; 
Chasmops, McCoy; Pterygometopus, Schmidt; T rimer ooephalus, 
McCoy; Portlockia, McCoy; Cryphceus, Green; Coronura, Hall 
and Clarke; Odontocephalus, Hall and Clarke; or Corycephalus, 
Hall and Clarke. 
We imply a doubt because the subject of our PI. xxxix. tig. 12, 
appears to foreshadow a third section or genus, but the material 
is too scanty to enable us to pass a definite opinion. 
Genus Phacops, Emmrich, 1839. 
Phacops in its restricted sense, following the researches of 
Salter* and Schmidt,! and to some extent of Barrande^ also, omit- 
ting other minor characters, is distinguished from other members of 
the Phacopidse chiefly by the presence of the two anterior pairs of 
glabella furrows, generally linear in character, and of which the 
first or anterior pair frequently consists of two branches. The 
fore part of the glabella, formed by the frontal and lateral lobes, 
is, as a whole, cut off from the neck segment by the intervention 
of a supplementary ring, termed by Barrande the " intercalary 
ring " (anneau intercalate )§. Barrande used this feature as one 
of the chief distinguishing points between the only two genera 
recognised by him in the Bohemian Silurian rocks, Phacops and 
Dalmania (vel Dalmanites). This eminent author considered 
* Mon. Brit. Sil. Trilobites, Pt. 1, pp. 13 and 14. 
t M<Sm. Soc. Imp. Sci. St. Petersb. 1881, xxx. (7), No. 1. 
X Syst. Sil. Boheme, 1852, i. p. 498. 
§ Loc. cit. p. 505. 
