[bell] new genus of CHARACEAE AND NEW MEROSTOMATA 167 



meral portions of these segments are defined from the axial portions 

 in some segments by narrow, curved longitudinal grooves. They 

 end in acute projections. The succeeding and last segment is formed 

 of a fusion of somites. Anteriorly on this last segment there are two 

 free epimeral projections. A small hemispherical tail-like area is 

 marked by a median triangular depression suggesting articulation with 

 a caudal spine which has been lost. In one specimen the entire posterior 

 segment is lacking. 



The total length of the abdominal portion is 8 mm., the width 

 across the 4th segment 7.5 mm. On account of the partial covering 

 of matrix and overlapping of the posterior shield there is a false 

 appearance of a marked contraction of the body at the first two seg- 

 ments. 



In the more complete specimen the cephalic shield has suffered 

 rotation to the left and on that side overlaps all but the outer corner 

 of the hinder shield. On account of this distortion and the presence 

 of minute slips within the test it is difficult to trace the precise limits 

 of the two shields in the axial region. Fig. 14 is a drawing to show 

 more clearly the relations. A portion of the headshield ai has been 

 broken ofif and slipped under A. There is little evidence such as 

 transverse wrinkling to indicate any important foreshortening, so 

 that in its natural position shield A probably overlapped somewhat 

 onto the anterior portion of shield B. A similar overlapping is 

 apparent in the second specimen, although the margin of the fore 

 shield is not complete. It seems evident at least that the two shields 

 are not fused together in the axial region. 



The shell substance is thin and lacks the scale-like ornamentation 

 of the Eurypterids. 



Although the general contour of the body and of the large cephalic 

 shield resembles other Xiphosurians there is no apparent trilobation 

 of the body and the presence of a distinct post-cephalic shield is unique. 

 Were it not for the presence of the double shield and the absence of 

 trilobation Schistaspis would be very similar to Belinnrus, which has 

 an abdomen of eight segments, of which the 7th and 8th are consoli- 

 dated, in addition to a long, slender telson. Euproops has seven ab- 

 dominal segments fused together, besides a short caudal spine. 



