APPENDAGES AND NERVOUS SYSTEM OF APUS CANCRIFORMIS, 353 
‘the proximal lobe” (that basewards, in relation to the same 
attachment). 
It is important to note this development, since in some 
Phyllopods and other Crustacea it is very greatly exagge- 
rated, and the flabellum practically divided into two moieties 
(see woodcut, fig. 1, XIX, XIV, and VI, Fd). 
The muscles distributed to the endites and the flabellum 
are more strongly developed in the pre-genital than in the 
post-genital appendages of the locomotor series, as may be 
seen by comparing Pl. XX, fig. 9, with fig. 11. Whilst in 
the post-genital appendages endite 2 ceases to have a distinct 
muscular slip supplied to it, this endite, like all the others, 
has in the pregenital series a muscular slip from the great 
muscle of the axis, which is distributed to the five distal 
endites. The sixth endite has, in addition, a separate 
muscle, which runs parallel with the common muscle of the 
endites, and the first endite or gnathobase has also its own 
special muscles. The muscular supply of the sixth and first 
endites is the same in all the thoracic aud abdominal appen- 
dages, excepting the first two of the thoracic series (two 
anterior thoracic feet of authors). 
The bract is in all cases devoid of any muscular supply— 
a fact which is not without importance in the determination 
of its homologue in other Crustacea. 
The appendages in front of the ninth of the thoracic 
series have a form closely similar to that drawn in Pl. XX, 
fig. 9, the endites becoming slightly more elongated in form, 
and the axis also elongated, so as to separate the endites 
from one another in those nearest the first two thoracic 
feet. 
The first two thoracic feet require special description. 
Second thoracic foot.—This appendage is drawn in Pl. XX, 
fig. 8. The most important feature which it presents, as dis- 
tinguished from those behind it which have been already 
considered, is the jointing of the corm or axis. The corm 
is divided into two segments or pieces by a soft fold of its 
chitinous cuticle, and muscles are attached to the distal 
segment so as to move it upon the basal segment. To the 
basal segment (Az!) are attached the two proximal endites 
(en! and en*), whilst the four distal endites, the flabellum and 
the bract, are attached to the distal segment (Adz). The 
endites are much elongated and notched at their margins, 
retaining, however, a flat or lamelliform character. The 
terminal endite (en®) is strongly denticulate and has its ex- 
axial process markedly developed, whilst the notch in the 
axis into which this process fits is peculiarly constructed, as 
