REPORT OP THE STATE PALEONTOLOGIST 1902 1099 



entiated; the telson long, probably equal in length to the five 

 preceding segments. 



The cephalothorax is broad, rounded in front, the sides 

 curving out near the genal angles, and the base straight, or 

 very gently curving over the middle portion, and extending a 

 little forward near the sides. The margin is beveled in for a 

 distance, in the average sized individual, not exceeding 2 mm 

 in the widest part or in front, narrowing and fading out at the 

 genal angles. The extreme edge is slightly upturned. The com- 

 pound eyes are separated by one half the breadth of the shield, 

 with their bases in line with its center. They are prominent, 

 reniform, broader at the anterior ends, and one fifth as long 

 as the shield. The ocelli are situated on a faint tumescence 

 between the centers of the compound eyes. They are rather 

 large and separated by about their own diameter. Near the 

 basal edge of the shield is a pair of sharp, raised, triangular 

 scales, one on either side of the axial line. In some cases there 

 is a row of shallow, flat bottomed pits on the beveled margin. 



The abdomen increases slightly in breadth from the base of 

 the cephalothorax to the third segment, then tapers to the 

 telson, there being no apparent constriction between the pre- 

 abdomen and postabdomem The tergites are comparatively 

 short, the length averaging a little less than one fifth the 

 breadth. They are broadly concave along the middle of their 

 posterior edges, and each carries, bordering this curve, four 

 raised, triangular scales like the two on the posterior border 

 of the cephalothorax and the middle two in line with them. 

 The five sternites are medially cleft and marked by transverse 

 sutures, which give to each the appearance of having been 

 formed by the fusion of two plates. With the exception of the 

 first or operculum, they have the anterolateral angles projected 

 forward into small lobes. In the operculum these angles are 

 noticeably rounded away, and the anterior edge is projected 

 into a broad median lobe. In the female the second sternite 

 has a similar lobe. The annulate segments, or sclerites, com- 

 prising the postabdomen increase in length and decrease in 

 breadth from the first, which is very broad and short, to the 



