— 2o6 — 
cells etc. a Neuroglia forming the central, vertical sep- 
tum dividing the nerve-cord longitudinally (compare fig. 
lo, a & fig. 14). Igc Large ganghon cells with deeply 
staining protoplasm, with spongioplasmic fibres issuing from 
the sheaths of the cells, and with small lightly staining masses 
of primitive tubes Q). np Nervous process. gc, gc^ Large 
ganglion cells with deeply staining protoplasm. sgc Small 
ganglion cells with lightly staining protoplasm. sgc^ Gan- 
glion cell of mesial size with a small mass of deeply 
staining protoplasm. nf, nf Neuroglia-fibres and longitu- 
dinally transsected tube-sheaths uniting with the sheaths 
of the ganglion cells. (Fixed and stained as fig, 66.) 
Fig. 68. Homarus vulgaris (Magnified 100 diameters.) Ganglion 
cell from an abdominal ganglion ; constructed from a series 
of transverse sections, partly by help of the cam. lue. 
(Fixed in chromo-aceto-osmic acid, stained in accordance 
with Heidenhains hæmotoxylin method. 
» 69. Homarus vulgaris. (Magnified 132 diameters; Zeiss A A, 4. 
Cam. lue.) Ganglioncell from a thoracal ganglion, observed 
in a transverse section (chromo-silver staining); the proces 
could be traced directly into a peripheral nerve. 
» 70. Homarus vulgaris (Magnified 3 So diameters; Zeiss CC, 4. 
Cam. lue.) Unipolar ganglion cell from a chromo-silver 
stained section of a thoracal ganglion. The nervous pro- 
cess subdivides and is broken up into slender branches. 
The slender fibres issuing from the body of the cell are 
neuroglia-fibres issuing from its sheath. 
» 71. Lumhricus agricola (Magnified 620 diameters; Zeiss F. i. 
Cam. lue. from the microscope directly upon the stone.) 
Lateral part of a transverse section of the ventral nerve- 
cord. a—h Ganglion cells. c Ganglion cell containing 
two nuclei. pe Perineurium. m Muscles. ct Septa and 
fibres of comective tissue issuing from the perineurium. 
nu Neuroglia. ds Dotted substance. nt, nt\ nf^ Transsected 
nerve-tubes of various sizes. Us, Us' Sheaths of two of 
the three colossal nerve-tubes. n, n' Neuroglia-nuclei. 
(Fixed in chromo-aceto-osmic acid, stained with Dela- 
field's hæmotoxylin). 
» 72. Lumlricus agricola. (Magnified 750 diameters; Zeiss F, 2. 
Cam. lue.) Ganglion cell from a transverse section of 
the ventral nerve-cord. 
