98 
Gustaf T. Troedsson 
pair of lobes the glabella is scarcely 2 /3 as wide as the cheeks. Frontal limb well developed, 
broadest in its median part. Eyes very large reaching from the anterior pair of lateral furrows 
close to the neck furrow. The posterior branch of the facial suture strongly sigmoid. Genal 
angles produced into stout spines. Surface of head-shield, like that of thorax and pygidium, 
marked with a close granulation. Pleurae of thorax with well developed, oblique furrows and 
pointed ends. Pygidium with terminal spine. Axis with 12 visible rings, occupies a third of the 
width of the tail. Pleurae on each side 9. Oblique furrows considerably coarser than the inter- 
pleural furrows; the two halfs of the pleura about equally broad. The anterior pleurae fairly, bent, 
the posterior rather straight. The limb about as broad as the anterior pleurae, near the front 
narrower than behind, inwards undulating, outwards more even. 
D. Kiaeri seems to be allied to I), obtusi-caudatus Salt, from the Upper Caradoc of 
England. 
Ampyx acus n. sp. 
Pi. II, f. 24. 
Cranidium triangular of outline, 2 mm. in length at most. Axial furrows 
parallel; in their posterior ends they pass over into the marginal furrows. Gla- 
bella broad, flattened in its posterior corners, for the rest, however, strongly con- 
vex and even medianly carinated. The convexity is hardly 1,5 times as long as 
wide and has its maximum of height and breadth a little before the middle, from 
where it decreases to both ends. In front the glabella is produced into an 
acicular point as long as the rest of the glabella. In the posterior end of the 
glabella there is a pair of deep impressions. These are, like the axial furrows, most 
conspicuous on internal casts. Fixed cheeks convex of outline and reaching of 
the length of the glabella. Posterior marginal border much wider in the interior 
end than in the exterior one. Surface marked with thin, raised, lines, on fixed 
cheeks running nearly parallel with the facial suture. — Free cheeks, thorax and 
pygidium unknown. 
Ampyx acus seems to be most allied to Ampyx setirostris Angelin from the 
Chasmops beds of Dalarna. 
Acidaspis Olini n. sp. 1 
PI. I, f. 29. 
Only cranidia are met with. 
Glabella strongly convex, a little longer than its width at the base; from 
the well marked axial furrows two pairs of lateral furrows proceed, obliquely in- 
wards-backwards directed. Together with the false axial furrows, forming their posterior 
continuation, and the broad neck furrow, they cut off two pairs of lateral lobes, 
which are very narrow, the basal ones being the longest, and acuminated on the 
This species belongs to the subgenus Leonaspis Richter (se the note on p. 77). 
