274 E. A. ANDREWS 
The new growth on the median side of the basal part of the endo- 
podite (fig. 27), is a sort of knob set on a neck and inclined at 
about 45° to the axis of the endopodite. Its form is not spherical 
but rather more that of a short cylinder on a slightly shorter neck. 
The long axis of the cylinder and of the neck is at an angle of 45 
degrees to the side of the endopodite. Not only this protruding 
knob must be reckoned as part of the future triangle but also the 
neighboring widened area of the endopodite which is depressed 
as indicated in the shadow in fig. 27 and which will be the de- 
pressed anterior face of the future triangle. In fact this depres- 
sion is accentuated by the position of the knob, which not only 
stands out as represented in the figure but also rises up toward the 
observer; that is, anteriorly away from the general plane of the 
endopodite. The base of the flabelliform distal part of the endo- 
podite is continued on to the external distal corner of the basal 
region of the endopodite as a ridge standing up above the de- 
pressed area, and forming what will be the guide ridge of the per- 
fected organ. 
In a small male, 38 mm. long, in October, the second pleopod 
had advanced to the state of perfection shown in fig. 28, which is 
an external view of a left accessory stylet, which was about three 
times as long as the one shown in fig. 27. The muscles in the 
protopodite remain as before, though not so well seen from this 
point of view, and the same is true of the endopodite and the exo- 
podite. The protopodite and the exopodite have grown so large 
and massive that the slender exopodite is much subordinated. 
The great increase in the basal part of the endopodite, along with 
the enlargement and specialization of the triangle, leaves the plu- 
mose terminal part of the endopodite as a slender palp-like rem- 
nant of the original end of the endopodite. The triangle is now 
so much longer at its free edge than at its attached part that it 
has the adult triangular form when seen from the median face; or 
more explicitly, the obliquely set ‘cylindrical knob of fig. 27 has 
grown so much longer at its free edge than at its attachment that 
the length between its ends about equals the distance of the prox- 
imal end or elbow from the main mass of the endopodite, which 
