96 
Gustaf T. Troedsson 
Trilobitae. 
Dalmanites eucentrus Ang. (Olin) 
PI. I, f. 19—24. Text fig. 10 and 11, p. 59—60. 
and 
Dalmanites mucronatus Brongn. 
PI. I, f. 26 — 27. Text fig. 12 and 13, p. 69. 
are defined as follows: 
Head 
Dalmanites eucentrus 
Dalmanites mucronatus 
Frontal limb 
very thin, commonly not vi- 
sible; 
broader and well developed. 
Lateral furrows of 
glabella 
shallow ; 
deep. 
Frontal lobe 
without tubercles; 
covered with coarse tubercles. 
Posterior branch of 
the facial suture 
slightly sigmoid; 
strongly sigmoid (young speci- 
mens; the largest specimens 
more like D, eucentrus). 
Eyes 
reaching from the anterior to 
the middle (large specimens) 
or to between the middle and 
posterior pairs of furrows 
(ephebic specim.); 
Ephebic specimens: large, rea- 
ching .from the anterior to 
the posterior pair of lateral 
furrows. Larger specimens = 
D. eucentrus. 
Tail 
D. eucentrus 
D. mucronatus 
Numbers of visible 
axial rings 
(8 )9, 
11—13. 
Numbers of visible 
pairs of pleurae 
6( — 7), 
8—9. 
Furrows of lateral 
portions : 
Oblique and interpleural fur- 
rows equally developed. 
Oblique furrows commonly more 
marked than the interpleural 
ones. 
Pleurae : 
The anterior part about half as 
broad as the posterior one 
which widens outwards. 
The two halfs equally developed. 
Neanic specimens sometimes 
= D. eucentrus. 
