936 
ME. J. LOCKHAET CLAEKE ON THE DEVELOPMENT OF 
Fig. 18. A portion of one of the posterior white columns of the spinal cord of a human 
foetus of five months, showing the numerous nuclei with which it is inter- 
spersed; magnified 670 diameters. 
Fig. 19. A transverse section of the spinal column and cord of the chick at the end of 
the fifth day of incubation ; magnified 60 diameters. 
Fig. 20. A similar section of the cord at the end of the ninth day of incubation: — 
large mass of nucleated connective tissue replacing the inner portion of the 
posterior columns. 
Fig. 21. A transverse section of the cord of the same, through the lower part of the 
sacral enlargement. 
Fig. 22. A similar section a little higher up, between figs. 20 & 21, 
Fig. 23. Part of an intervertebral ganglion and surrounding connective tissue of a foetal 
sheep 1 inch long: — a, nuclei or small cells of the ganglion; J, connective 
tissue on its outer surface ; magnified 420 diameters. 
Fig. 24. The same from a foetal sheep If inch in length. The nerve-cells have 
enlarged and are connected by a continuous network with each other, with 
the nerve-fibres, with intervening granular nuclei, as at h\ and with nucleated 
fibres connecting the ganglion with the lamina of the vertebra, at 5. At a 
indistinct nuclei are seen in the interior of the cells; magnified 420 dia- 
meters. 
Fig. 24*. Cells from the same at a little later period of foetal life ; X 420. 
Fig. 25. Portion of a transverse section of the intervertebral ganglion of a foetal sheep 
about 3 inches long. The cells have increased in size, are pyriform, a well- 
defined nucleus has made its appearance in each, and between the cells the 
interspaces are occupied by small angular or elongated nuclei. 
Fig. 25*. Cells from the intervertebral ganglion of a human foetus of nine weeks; from 
one of the ganglia represented at e, e, fig. 8, Plate XLVI. 
Fig. 26. A nerve-fibre dividing into branches to be connected with cells. From the 
intervertebral ganglion of a sheep 3 inches long; magnified 670 diameters. 
Fig. 27. Another fibre connected with cells by dmsion. 
Fig. 28. A group of cells in their natural position connected with ramifying nerve-fibres; 
small nuclei occupy the spaces between them ; magnified 420 diameters. 
Fig. 29, Portion of such a group, showing the manner in which the nerve-fibres are 
connected with it. 
PLATE XLVIII. 
Fig. 30. Isolated nerve-cells from the same. 
Fig. 31. Group of cells from the intervertebral ganglion of a foetal sheep 8 inches long; 
magnified 420 diameters : each cell is enveloped in a thick nucleated sheath. 
Fig. 32. Group of cells, with nerve-fibres, from the anterior part of one of the interver- 
tebral ganglia of the chick at the end of the ninth day of incubation ; magm- 
