264 E. A. ANDREWS 
the complex large part of the appendage that bears a terminal 
flabelum and the remarkable side protuberance, found on no other 
limbs, which may be called the triangle. 
Describing the entire stylet from the base outward, we see 
that the protopodite is chiefly a very strong flattened bony mass 
extending diagonally inward so that while the endopodite and ex- 
opodite are about parallel to the median line of the animal the 
protopodite forms an angle of 45° with it. This makes it possible 
for the endopodites of the two stylets tocome together at the me- 
dian line and for the endopodite of each side to lie upon the groove 
of the base of the first stylet, like a lance in its rest, although the 
bases of the two second stylets are fastened to the sternum of the 
second abdominal somite some distance from the median line. 
The protopodite is not entirely one-jointed but at its base is a soft 
membrane where it is joined to the sternum and in this are two 
large calcified plates, (figs. v and vr) besides two minute ones, 
(fig. vit) all of which together make a narrow basal section of the 
protopodite. Dissection shows there are muscles passing from 
this base of the protopodite into the sternum that may depress 
and elevate the appendage. 
The protopodite is some 6 mm. long, 2 wide and 14 thick. The 
exopodite is a slender filament some 9 mm. long and 4 mm. thick; 
a slightly flattened tapering cylinder set with long setae on exter- 
nal and median face. The setae are really plumose and together 
form a sparse brush. The exopodite is obscurely divided into 
some twenty segments. The basal 2 mm. is partly calcified, the 
rest membranous. It articulates freely with the outer distal 
corner of the protopodite so that it may be moved from the posi- 
tion of rest parallel to the endopodite, outward through 90° and 
swung back and forth some 45°. The tip of the exopodite often 
lies dorsally within the cavity or hollow of the triangle, and may 
have some use as a cleaning brush. 
The endopodite is the stout calcified mass, roughly cylindrical 
but flattened from before back, some 9 mm. long on the median 
(fig. vt) and 7 mm. on the external face (fig. vim), and bearing at 
its distal end a flagellum on the external side and the flat triangle 
on the internal side. This bony mass is set on the protopodite 
