CRUSTACEA AND ARACHNIDA OF THE CARBONIFEROUS ROCKS. 523 
The tarsus bears a similar marking on its lower margin. Each articulation 
is edged with the Eurypterus scolloping (see Pl. XX VIII. fig. 11). 
A specimen (fig. 11a), showing the tarsus and hand with the double claws, 
and projecting spines at the joint, which in all likelihood belonged to this 
genus, was obtained from Lennel Braes, and described by me as scorpion in 
my paper on the Scorpions of the Scottish Border. 
Another portion of a limb, apparently a walking leg made on the type of 
scorpion, comes from Lennel Braes. The shaft of one joint measures 5 cm. 
from articulation to articulation. It is laterally compressed, has serrations 
on both margins, is narrowest about its middle, where it measures 11 mm. 
across, and widens at its lower articulation to 15 mm. It has a gentle upward 
curve. The upper articulation of this joint is set at an angle of 45° to the long 
axis of the shaft, and it occupies only about the anterior half of the end on 
which it is placed, the other half being produced backwards as rounded heel- 
like projection. The lower extremities of this joint is produced considerably 
beyond the articular line in the form of two triangular areas down the outside, 
of which the ornamental serrations are continued, the inner sides being plain. 
Between these the next joint is wedged, and a portion of it with its serrated 
anterior edge is seen to be bent off at an angle of 35° towards the posterior 
margin. The joint first described must then correspond with the third joint 
in the scorpion’s limb, where the leg doubles both ways. Fig. 23 is a repre- 
sentation of this fossil, natural size, with a scorpion’s limb drawn for comparison, 
and the portion of the corresponding joint which exhibits a different scnlptur- 
ing is shown in fig. 14, also from Lennel Braes. Fig. 15 represents the apical 
portion of another joint from Langholm, which, in addition to similar triangular 
projections to those above described, shows the Eurypterus scolloping on the 
articular portion. As well as the usual fringes, it has a strong ridge bearing 
serrations on its mid line. It is very much like the third joint of the palpus of 
a scorpion, which has just such crests of tubercles. 
Besides the portion described there are several fragments of more or less 
interest in the Survey Collection, exhibiting a considerable variety of pattern 
and sculpturing. Some of these pieces must have belonged to individuals 
as colossal as the G. Caledonicus, and others to mere pigmies; but it would be 
imprudent to attempt to make species from ornament alone without knowing 
what part of the body it graced, as the same Eurypterus often exhibits different 
kinds of decoration on its several parts: Among the fragments obtained from 
Langholm are the remains of what has been an individual almost as large as 
the P. Caledonicus described from Lennel Braes, and which exhibits an 
ornamentation somewhat similar to that species. The specimen occurred in 
such a manner that only fragments of it were procurable by the collectors. 
One piece is of great interest, as it still holds between the upper and lower 
