170 S. II. SCUDDER ON SPINED MYRIAPODS 



extended, would be about 70 ram. ; it is of a nearly uniform width of 3.1 mm. throughout, 

 but tapers posteriorly especially on the apical fourth, so that the hinder extremity is only 

 2 mm. broad ; at its broadest part it measures 3.3 mm. ; perhaps by its mode of preservation 

 it does not show the entire breadth, for the legs, which in other specimens of the species 

 are no longer than the body, are here 3.75 mm. long. The spines agree in character 

 with those of the last specimen mentioned, but in only one or two places can the anterior 

 spinule be recognized. The segments of the body are very badly preserved and are hardly 

 twice as broad as long ; the structure of the surface can nowhere be distinguished, but 

 some signs exist of the marked distinction between the anterior and posterior portions of 

 the segments ; the head again is badly preserved ; it is very full in front, and bears a 

 distinct, long and slender antenna, as long as the depth of the head, originating, on a side 

 view, above the middle of the head, and consisting of seven subequal joints ; the first and 

 second are slightly longer than broad, rounded subquadrate, a little larger at the tip than 

 at base ; the fifth and sixth similar but smaller, the last similar but much smaller, and the 

 third and fourth like the basal ones, but longer and more cylindrical, perhaps a little more 

 than half as long again, or twice as long as broad. The whole antenna is 3 mm. long and 

 in the middle 0.3 mm. broad. 



Three specimens of this species, two of them with counterparts, are found in Mr. Arm- 

 strong's collection ; one of them with its counterpart shows twenty-three segments of the 

 posterior portion of the body lying in a nearly straight line, partly on its side, with spines 

 on one side and legs on the other. The total length is 60 mm. and the broadest part 4.5 

 mm. wide, a width which is retained with slight diminution until the last 20 or 25 mm. are 

 reached, when the body tapers more rapidly, and just before the tip is reduced to 3.25 

 mm. As in the last specimen, the anterior basal spinule of the spines is rarely visible, and 

 the spines themselves are unusually slender and pointed, and rather more than half as long 

 as the width of the body. The legs are slightly shorter than the width of the body, and 

 the segments, which are much flattened, and poorly preserved, show signs of the granula- 

 tion of the surface and the difference of level of the anterior and posterior portions which 

 is characteristic of the species. 



The other two specimens referred to this species are very imperfect and add nothing to 

 the points already brought forward. 



This species differs from all the others in the coarser pitting of the surface and in the 

 deep and sudden contrast in elevation between subsegments. The segments are also much 

 longer than those of the preceding species, the legs longer than usual and the spines 

 rather shorter, although of the same simple character. The subdorsal spines are separated 

 at an unusual distance, and there is a transverse sulcation between them, in which points 

 it differs markedly from those of all the other species ; it seems apparent, therefore, that it 

 cannot be confounded with the other specimens referred by Meek and Worthen to their 

 original E. armigera. This species also shows scarcely any sign of tapering, excepting 

 toward the hinder extremity and here very gradually ; in this respect it presents features 

 very different from the following species. All the specimens known came from Mazon 

 Creek. 



