116 Wicciam A. Hivron, 
more or less terminal, trunks were well seen. Fig. A shows a 
reconstruction from such a specimen; not all of the branches are 
shown. In preparations stained with hematoxylin and picro-fuchsin, 
there was a good differentiation of the nerve strands running to 
the surrounding muscle fibers and connective tissue. In such speci- 
mens the nerve trunks could be traced for long distances from 
the ganglion out to muscles and to the surfaces of the mantle. 
In favorable specimens of this sort numerous nerves of moderate 
and small size were also seen coming off from the body of the 
ganglion. 
In the model represented in Fig. B there are three rather large 
branches shown at the oral end (up in the figure) All of these 
run up towards this-part of the animal between muscle fibers, often 
crossing from side to side through the thickness of the mantle. They 
all undoubtedly supply the musele fibers with which they are closely 
associated, and also send fibers to the surfaces of the mantle. The 
central branch, for a time at least, runs along the gland duct. In 
Fig. A the duct is shown, but no demarcation is shown between 
the two branches, since they run close together. A more lateral and 
a more caudal branch, shown in Fig. B, are represented by stubs 
only in Fig. A. The three terminal branches shown in Fig. B are 
close together for quite a distance as they leave the ganglion, for 
a longer distance, in fact, than is to be inferred from the drawing, 
since their basal portions are represented as one mass, while from 
sections it is seen that they are distinct down almost as far as the 
first pair of lateral branches. The larger trunks of the ganglion 
are often much changed in shape at various parts of their course, 
as they mould themselves about muscle bands. 
In a specimen of a nearly related species, all the branches at 
the oral end were followed in dissections out to the bases of the 
oral tentacles. In the specimen modeled, the branches were cut off 
at that end; but if these branches correspond to those of the other 
species, then we might expect that they also terminate in the region 
of the oral tentacles. At least they probably contain both afferent 
and efferent fibers. The several larger nerves at the atrial end 
also contain fibers supplying muscles and from their position and 
general distribution seem to contain afferent fibers also. In the 
specimen shown in Fig. B there were found in the middle part of 
the ganglion three large nerves, four slightly smaller ones, and about 
as many very short and rather minute nerves. Most of these trunk 
