314 The Alligator and Its Allies 
of each of these small areas. Although they show 
no connection with the central nervous system, 
these structures appear to be the rudiments of the 
sympathetic nerves. 
Figure 17f is in the region just in front of the 
hind legs. The abdominal walls are here unfused, 
and into the unenclosed body cavity projects the 
intestine (z), supported by a narrow mesentery 
and surrounded by a comparatively thick mass of 
mesoblast. The Wolffian body and duct form a 
mass of considerable size on each side of the 
mesentery. The Wolffian body is cut near its 
posterior end and consists of smaller tubules than 
in the more anterior regions. The Wolffian ducts 
(wd), on the other hand, are very large and are 
much more clearly distinguishable from the Wolf- 
fian tubules than in the preceding sections. The 
Wolffian ridges (wr) are very marked projections 
on the sides of the body, and in a region farther 
caudad become especially developed as the poste- 
rior appendages, to be described in connection with 
the following section. Both spinal ganglia are 
shown in this figure (sg), and in connection with 
the left ganglion the spinal nerve (sz), extending 
ventrally as far as the level of the Wolffian 
duct. The sympathetic nerve rudiments do 
not extend so far caudad as the plane of this 
section. The dorsal end of each muscle plate 
(mp) is seen, in this and other sections, to be 
slightly enlarged to form a round knob; this 
