EOBUTHUS. 15 



laminate and bilobed ; the lobes are semicircular and considerably overlap the 

 anterior portion of the sterna behind them. No such laminate lobes are found on 

 the last sternal plate of the abdominal portion of the opisthosoma; this sternum is 

 exactly like that of recent Scorpions and has a pair of abbreviated granular crests. 

 The interest of these laminate lobes on the sterna which belong morphologically to 

 the fourth, fifth and sixth segments of the opisthosoma, lies in their general 

 resemblance to the gill-bearing appendages of the same segments in Limulus. I 

 can find no trace of stigmata upon these sterna; hence I suppose that the respira- 

 tory lamellae lay beneath them as they do in Limulus. In possessing these lobate 

 sternal plates, the Scorpion now described is more like Limulus than is the 

 Silurian Scorpion Palseojjliomts; and it supplies one more valuable link in the 

 chain of evidence pointing to affinity between the Scorpions and Xiphosurse. 



The fragments of limbs of the prosoma that remain resemble those of recent 

 Scorpions, and offer nothing specially worthy of comment. 



Measurements in mm. — Total length from anterior end of sternum of prosoma 

 to posterior end of last abdominal segment of opisthosoma about 41 ; length of 

 coxa abutting against sternum 11 ; length of the sternum 4?, width about 3"5 ; width 

 of genital operculum 4o, length 3"5 ; length of sternum of pectinal segment 4, 

 anterior width 4-, posterior width 9"5 ; length of pecten about 9 ; width of penulti- 

 mate sternal plate of abdomen 21 ; length at the side nearly 9. 



A single specimen from Sparth, near Rochdale, in the collection of Mr. F. Holt. 



This specimen shows the ventral surface of the abdominal portion of the 

 opisthosoma, part of the ventral surface of the prosoma, and portions of some of 

 the limbs. 



So far as can be judged, this specimen differs from that of E. ralcovnieensis in 

 being larger and in having the sternal plate of the pecten-bearing segment 

 relatively much larger. In E. ralcovnieensis the length from the sternum of the 

 prosoma to the end of the abdominal portion of the opisthosoma is probably about 

 34 mm. In E. holti, the same area, although contracted, is 41 mm. ; and in the 

 latter the length of the sternum of the prosoma is about equal to that of the sternal 

 plate of the pectines, while it is much less than half its posterior width. In E. 

 ralcovnieensis, on the contrary, the sternum of the prosoma is longer than the 

 sternum of the pectines and half its posterior width. I have no doubt that many 

 more differences will be discovered when better material is available for 

 examination. 



I provisionally refer to this species a specimen from the Shipley claypit in Dr. 

 Moysey's collection. It consists of the abdominal portion of the opisthosoma, 

 showing the terga, some of the sterna, and a considerable portion of one of the 

 legs of the last pair. The segments, however, are apparently telescoped to a 

 considerable extent, thus appearing to be very much shorter than they are in 

 reality. The tergum and sternum of the last segment of the abdominal portion 



