— 200 — 
Fig. 27. (Magnified 620 diameters; Zeiss F, i.) Section through 
a large ganglion cell and the root of its process, the 
lightly staining contets (a) of which arises from a union 
of bundles of primitive tubes. b Transsected spongio- 
plasmic fibres, with which the spongioplasmic walls separat- 
ing the primitive tubes, unite. cm Sheath of a ganglion cell. 
» 28 & 29. (Magnified 620 diameter; Zeiss F. i.) Parts of suc- 
cessive sections through the same ganglion cell, selected 
from a series of sections to show how the lightly stain- 
ing contents (p, p) of the process penetrates into the 
protoplasm of the cels surrounded for some distance by 
deeply staining fibres (s, s'). h Such fibres transsected. 
a & s'' Similar fibres penetrating into the protoplam of 
the cell. cm Sheath of the cell. v, v Transsected bundles 
or small masses of primitive tubes, nv Cavities in the 
sheath of the cell into which cavities the protoplasm of 
the cell partly extends. 
Plate lY, 
The illustrations are drawn under camera lucida from the mi- 
croscope directly upon the stone. The preparations (exept fig. 41) 
are fixed and stained in the same way as in Plate III. All the 
illustrations are tåken from ventral ganglia of 
Homarus vulgaris. 
Fig. 30 — 33. (Magnified 350 diameter; Zeiss CC, 4.) Successive 
sections through the process of a ganglion cell, selected 
from a series of transverse sections through an abdominal 
ganglion. In fig. 30 the process is seen quitting the cell 
in fig. 33 it is divided into two branches {a & 6). p, c Con- 
tents of the process; near the cell (fig. 30) this contents 
is lightly stained, in a greater distance from the cell (fig. 31) 
it becomes more deeply stained until it, at a certain distance 
(fig. 32), becomes quite dark. pr Protoplasm of the ganglion 
cell. sf Spongioplasmic fibres, penetrating into the proto- 
plasm of the cell and {sf) into the contents of the pro- 
cess. sf Similar spongioplasmic fibres occurring in the 
external layers of the contents of the process. cm Neu- 
roglia-sheath of the ganglion cell. is Inner neuroglia-sheath 
enveloping the process. nm Concentric layers of neu- 
roglia surrounding the process. 
