— 202 -- 
staining mass of primitive tubes, ss Spongioplasmic septa 
and fibres occurring in the lightly staining mass. 5s' Si- 
milar septum with a little deeply staining protoplasm. 
v, v' Small lightly staining masses, cm Sheath of the cell. 
nm Neuroglia. 
Fig. 40. (Magnified 350 diameters; Zeiss CC, 4.) Section through 
a group of smallish ganglion cells in a thoracal ganglion. 
a Transsected processes issuing from the cells. n sh Peri- 
neurium enveloping, the ganglion, nm Neuroglia occur- 
ring inside the perineurium. 
» 41. (Magnified 750 diameters; Zeiss F, 2.) Section of the 
nucleus of a ganglion cell stained with hor ax-car mine. 
The nucleus has two nucleoli (a &h). c Thickenings in 
the chromatine-structure. n Membrane of the nucleus. 
» 42. (Magnified 750 diameters; Zeiss F, 2.) Sections of nuclei 
of ganglion cells. 
Plate V. 
All the illustrations of this plate are drawn under the camera 
lucida and from the microscope directly upon the stone. They are 
all tåken from preparations fixed in chromo-aceto-osmic acid, and 
stained with Delafields hæmatoxylin (and partly also with eosin or 
picric acid in turpentine). 
Fi^. 43. Nereis virens. (Magnified 1 1 50 diameters ; Zeiss. Hom. im. 
Vi8j 2.) GangUon cells, from a transverse section of the 
ventral nerve-cord. i — 5 gangUon cells in three of which 
processes (pr) are transsected. 2 Part of a ganghon cell. 
a Transsected nerve-tubes of the dotted substance. h Lightly 
stained part of the protoplasm of the cell i. cm, cm Sheaths 
of the ganglion cells. nu Neuroglia. n m Neuroglia- 
septum penetrating between the ganglion cells, and some- 
times dividing them into groups. lg Large dark granules 
in the protoplasm. 
» 44 & 45. Nereis virens. (Magnified 11 50 diameters; Zeiss. 
Hom. im. Vis» 2.) Ganglion cells, from horizontal sec- 
tions of the ventral nerve-cord. a Mesial, deeply stain- 
ing part of the protoplasm. h Peripheral, lightly staining 
layers of the protoplasm. sf Spongioplasmic fibres, pe- 
netrating into the protoplasm. cm, cm'' Neuroglia-sheaths 
enveloping the ganglion cells. nu Neuroglia. nm Thick 
neuroglia-septum. 
