10 THORELL & LINDSTRÖM, SILURIAN SCORPION FROM GOTLAND. 



carrying, in almost all scorpions, the two dorsal eyes. It is about half as long again as 

 broad, and its breadth nearly equals one-sixtli of the entire width of the cephalothorax; 

 the distance between its hind apex and the hind margin of the cephalothorax appears 

 to be six or seven tiraes as great as that between its front börder and the middle of the 

 frontal margin. A rather deep and strong median furrow extends from the hind apex 

 of the eye-tubercle to the transverse furrow mentioned above, and on both sides of 

 this median furrow the cephalothorax appears to be moderately convex, and is almost 

 smooth, except at the sides, where it is slightly uneven or coriaceous; also the portion 

 behind the transverse furrow is smooth, with traces of granulation towards the sides, 

 and of an impressed line along the hind margin. The eye-tubercle, on the other hand, 

 as well as the anterior part of the cephalothorax, on both sides of it, is densely ru- 

 goso-coriaceous, and the frontal lobes are distinctly granulated, the granules being low 

 and obtuse. We have not been able to detect, in our scorpion, any traces either of 

 dorsal or of Lateral eyes, and it is therefore doubtful whether it was provided with 

 visual organs, which are present in the Palceophonus found in Scotland by Dr Hunter. 

 Of the appendages of the cephalothorax, the mandibles or chelicerse (figs. 1 and 

 4, Md) are in a very good state of preservation. They are rather broad and strong, 

 measuring together, at the base, about two thirds of the greatest breadth of the ce- 

 phalothorax. Of the hand only the anterior part is visible: it is smooth, as is also 

 the inner finger, and it is of just the same form as in recent scorpions. The fingers 

 are strong, sul^triangular, gradually tapering toward the tip. The inner or immovable 

 finger (tigs. 1, 4 and 5, di) is nearly straight, but with the apex curved rather slightly 

 inwards, and the outer side is slightly convex or rounded longitudinally; its edge is 

 uneven or a little sinuated, but we have not been able to discern the teeth with which 

 it was probably armed. The outer or movable finger {dm) has nearly the same form 

 as the inner, being only somewhat bi*oader and longer, and the apex is longer and 

 strongly incurved; its edge has, in the upper margin, a row of four short blunt teeth. 

 There is probably no second (inferior) row of teeth on this finger: at least its apex, 

 which overlaps and crosses that of the inner finger, forms no »furca». The outer 

 finger appears to have been in part, especially towards the exteriör side, very finely 

 granulated. 



The palpi (fig. 1, Pl) are long and powerful; and from their being strongly com- 

 pressed, the different joints, especially the humerus and the brachium, have an unusually 

 short and broad aspect. The maxilla or coxal joint of the palpus is totally concealed 

 by the frontal lobes. The scapula or trochanter (second) joint {se), as seen from above, 

 is nearly triangulär, rather longer than broad at the apex, and somewhat densely and 

 irregularly covered with small tubercles or coarSe granules, some of which are abruptly 

 constricted so as to form a small wart at the tip (tig. 6). The next joint, the humerus 

 or femoral joint {h), is about half as long again as broad, and slightly broader than the 

 scapula and the bracbium: it is nearly rectangular or somewhat rhomboidal, with the 

 two longer sides straight and parallel; it shows no distinct keels, but several coarse 

 granules, which appear to have been, in part, disposed in a few longitudinal rows. 

 The brachium or tibial joint {br) is slightly narrower and somewhat shorter than the 



