LOWER HELDERBERG ROCKS. 
3.19 
Dalmania pleuroptyx. 
Dalmaiiia micrarus. 
Plate LXXY. Fig. 13 - 18. 
Asaphus micrurus : Green', Monograph, p. 56, Cast No. 19, f. 3. 
Asaphus hausmanni, in part, of authors. 
Pygidium triangular, convex, somewhat abruptly sloping at the sides, 
acute, attenuate behind. Axis very prominent, faintly subangular in 
the middle above, and regularly rounded towards the posterior extre¬ 
mity, rigid, scarcely declining below, and abruptly elevated from the 
.posterior marginal border; a narrow angular ridge extending from the 
extremity of the axis into the acute spiniform caudal termination. 
The number of articulations in the axis is twenty or twenty-one, which 
are strongly defined, and some of the anterior ones slightly bent for- 
