PALAEONTOLOGY OF NEW-YORK 
Fig. 5 : Euryptcrus lacustris. 
Fig. 5. A figure of the restored parts of Eurypterus lacustris f 
showing the lower surface of the carapace, the first four articula¬ 
tions of the body, the feet, etc. 
C, the carapace; M, the mouth; r, tho post-oral plate. 
m, m, the bases of the first joints of the feet, all or a part of which perform 
the function* of jaws. 
x, x, the flattened spaces which are covered by the next succeeding member 
when the parts are in their natural position. 
The feet on the right side of the figure are numbered 1, 2, 3, 4 and 5, 
corresponding to the orders of the pairs of appendages. 
On the left side of the figure, one of the third pair is numbered correspond¬ 
ing to what appear to be tho number of articulations. If we leave out the 
third joint, which may be only an apparent articulation, and the terminal 
spine, we have seven joints in this and the other feet. 
The swimming foot on the left side of the figure is similarly numbered. 
The fig. 7j has reference to the fixed ramus of the chela; s.5, the suturo by 
which this is joined to the posterior portion of the joint. 
In the articulations of the hody, the figures 1, 2, 3 and 4 have reference 
to the number of the segments in their order. The letters indicating tho parts 
of tho locomotive appendage have already been explained on a provious pago. 
