294 R. I. POCOCK. 



elevated upon a tubercle. If, indeed, such a tubercle existed 

 as is exhibited in tlie Gotland specimen, the eyes must have 

 been situated on its extreme anterior border. The presence 

 of these median eyes, and the probable absence of the tubercle, 

 are two important structural differences to distinguish the 

 Scotch specimen from the Swedish. 



Appendages. — The six pairs of prosomatic appendages 

 (i — vi, PI. 19) are preserved in a state of greater or less com- 

 pleteness, those on the left side being on the whole more 

 clearly defined than those on the right. 



The chelicerse or mandibles are, as in the Gotland 

 specimen, very large as compared with those of recent scor- 

 pions. The left chelicera, crushed out of shape and position, 

 shows no recognisable feature but a portion of the immove- 

 able digit. The right, on the contrary, is well preserved 

 and occupies its normal position, projecting straight for- 

 wards from the fore-part of the prosoma. The immoveable 

 digit is slender, pointed, and nearly straight; the moveable is 

 equally slender and pointed, but is lightly curved and armed 

 in the middle of its lower edge with a single tubercular tooth. 



It is noticeable that the digits of the chelicera are thinner, 

 and overlap at the apex to a much greater extent than in the 

 Gotland fossil. 



Owing to the distortion and displacement of the left che- 

 licera a portion of the matrix is displayed between the bases 

 of the two appendages just in front of the middle line of the 

 anterior border of the carapace. Pi'esumably it is this por- 

 tion of matrix which Mr. Peach describes — I think errone- 

 ously — as "a fleshy labrum (camerostome) between the bases 

 of the cheliceree." 



Chelge. — As in the Gotland specimen, these appendages 

 do not appear to differ in any essential respects from those 

 of recent scorpions. Their basal segments are too badly 

 preserved for delineation — a particularly regrettable circum- 

 stance in view of the fact that in the Gotland specimen they 

 are concealed from view. Hence it is impossible to surmise 

 whether they took a greater, less, or an equal shai'e in masti- 



