156 Silurian Fossils of Nova Scotia. 



axis. Axis wider than the lateral lobes, distinguishable (in casts) 

 from the lobes by a bending of the ribs and a scarcely perceptible 

 depression along that line ; annulations abruptly prominent ; seven 

 on the lateral lobes and nine on the axis, the anterior ones bend- 

 ing slightly backward at the line of division between the axis 

 and the lateral lobe ; each successive one bending more and more 

 abruptly till the last one approaches a rectangular turn ; the whole 

 curving gently forward at their extremities, and all terminating 

 abruptly before reaching the margin. Behind the seventh annula- 

 tion the axis is marked by two more annulations, leaving nearly 

 one-fourth of its length smooth. 



This species is described from the casts and impressions of the 

 caudal shield, so that the crustaceous covering is unknown. It is 

 readily distinguished by the broad not prominent axis, the rect- 

 angular direction of the annulations on the axis, and their abrupt 

 bending at the lateral furrow. An impression of a few imperfect 

 annulations of the body shows that they are strongly elevated, 

 much more so than in any known American species. 



31. Calymene Bltjmenbachii. var. 



Caudal shield somewhat semicircular, axis very prominent, 

 marked by about seven annulations, lateral lobes marked by five 

 ribs the four anterior ones bifurcating. Surface granulose. The 

 specimens are not sufficient to make any satisfactory determina- 

 tions regarding specific difierences. 



Fig. IT. Fig. 18. 



32. Dalmania Logani. N. sp. Fig. 18. 



The specimens are two or three imperfect cephalic shields, one 

 preserving the palpebral lobes, and others consisting principally of 

 the glabella, with two or three parts of caudal shields. There is 

 a fragment of a cheek which may be of this species. Cephalic 

 shield somewhat semicircular. Glabella ovate, wider in front and 

 truncate behind, depressed convex ; occipital ring narrow, pro- 

 minent ; occipital furrow bending a little forward in the middle 

 and curving gently backward in the middle of each side, and 



