THE SCOTTISH SILURIAN SCORPION. 295 



cation as compared with those of existing forms. The 

 second segments pi*oject on each side of the autero-lateral 

 angles of the carapace, and are granulai'ly sculptured. The 

 anterior surface of the third segment is apparently normally 

 crested above and below, and the fourth segment of the left 

 side shows traces of the basal prominence so noticeable in 

 living species. Granules are observable along the anterior 

 side of both these segments. The fifth segment (hand) of 

 the left side differs in shape from that of the right, being 

 more oval in form, with its posterior border in approximately 

 the same straight line as that of the distal segment, the 

 bulge being confined to the anterior surface as in the Got- 

 land specimen and recent species. On the right side the 

 hand is unusually globular, its posterior surface, probably 

 owing to crushing, being abnormally swollen. The fingers 

 are thinner, more taper, and straighter than in the Gotland 

 specimen and recent scorpions. No distinct joint between 

 the finger and hand is discernible, although presumably it 

 is the under side of the hand and of the moveable finger 

 that is exposed to view, both on the right and left sides. 

 It is possible that the shallow median longitudinal groove 

 observable on the finger of the right chela represents the 

 line along which the two fingers meet when closed. The 

 finger of the opposite side is similarly marked with a fine 

 sculptured ridge. 



Legs. — So far as can be ascertained the legs resemble 

 those of the Gotland specimen in length, strength, and seg- 

 mentation. As in other scorpions, and typically in all orders 

 of Arachnida, they increase in length from before back- 

 wards, the fourth pair being nearly half as long again as the 

 first. They consist, moreover, of what is doubtless the primi- 

 tive number of segments — namely, seven. Primitiveness of 

 segmentation is also shown by the subequality in length of 

 the individual segments — a character which, in conjunction 

 with the sharply pointed, practically clawless terminal 

 segment, serves to distinguish the legs of Palaeophonus 

 from those of all other scorpions, living or fossil. I say 



