DISTINCTIVE CHARACTERS OF THE CRAYFISH. 239 
pede is strongly serrated and wider in front than behind 
(fig. 44); the meropodite possesses four or five spines 
in the same region; and there are one or two spines at 
the distal end of the carpopodite. When straightened 
out, the maxillipedes extend as far as, or even beyond, 
the end of the rostrum. 
The inner or sternal edge of the ischiopodite of the 
forceps is serrated; that of the meropodite presents two 
rows of spines, the inner small and numerous, the outer 
large and few. There are several strong spines at the 
anterior end of the outer or tergal face of this joint. The 
carpopodite has two strong spines on its under or sternal 
surface, while its sharp inner edge presents many strong 
spines. Its upper surface is marked bya longitudinal de- 
pression, and is beset with sharp tubercles. The length 
of the propodite, from its base to the extremity of 
the fixed claw of the chela, measures rather more than 
twice as much as the extreme breadth of its base, the 
thickness of which is less than a third of this length 
(fig. 20, p. 93). The external angular process, or fixed 
claw, is of the same length as the base, or a little shorter. 
Its inner edge is sharp and spinose, and the outer more 
rounded and simply tuberculated. ‘The apex of the fixed 
claw is produced into a slightly incurved spine. Its 
inner edge has a sinuous curvature, convex posteriorly, 
concave anteriorly, and bears a series of rounded tubercles, 
of which one near the summit of the convexity, and one 
near the apex of the claw are the most prominent. 
