474, EDGAR J. ALLEN. 
The element E, Ant. 2 resembles in some points the members 
of this group. 
F, Type: the blue element in Th. IX, fig. 1. 
This element starts from a cell in the lateral mass, which 
lies very near the ventral surface. The fibre passes backwards 
and inwards, and then suddenly turns and runs forwards and 
outwards until it reaches the level of the anterior nerve-root, 
when it turns backwards and outwards and so leaves the cord. 
At the points where the fibre turns, branches are given off to 
the neuropile. Only one element of this kind has been ob- 
served to stain in the same ganglion at one time. 
The element has stained in Th. V—IX. In fig. 1, F Th. V, 
Th. VIII, Th. IX are inserted. 
The element F Th. I may also belong to this group. 
G. Type: the red element of Th. VI in fig. 1. 
This element starts from a cell in the median mass of gan- 
glion cells.' From the cell the fibre passes outwards, and after 
a somewhat curved course leaves the cord by the anterior root. 
It gives off two main branches to the neuropile, one of which 
gives off a third, the whole producing a figure somewhat 
resembling the trident figure of element E. Two or three 
elements of this type may stain on the same side of one 
ganglion. 
The element has stained in Th. II, III, VII—IX. In fig. 1 
it is inserted in Th. II, III, VI, VIII, IX. 
G Th. III is an element which stains in almost every pre- 
paration of young stages, and forms a useful landmark in the 
cord. 
H. Type: the red element in Th. X. 
Originates from a cell in the median mass, from which the 
1 As has already been stated (p. 5), the median masses of cells in the 
embryo divide transversely soon after the larva is hatched, the anterior portion 
going to one ganglion, the posterior portion to the ganglion behind it. The 
division takes place between the two groups of red cells in fig. 1, Th. VI 
and VII, at the level of the dotted line. 
