448 F. W. CARPENTER 
sions of the autonomic system. The histological investigations 
of Aronson, Retzius, Dogiel, Huber and others on various verte- 
brates have led to the general conception of such endings as peri- 
cellular, intracapsular networks of fine fibrils, surrounding and 
in contact with the cell-bodies of the postganglionic neurones. 
These end nets are not to be confused with the intercellular fibers, 
often intertwined and concentrically arranged about the ceil- 
bodies of the ganglia, but situated outside the cell capsules. Such 
fibers include the long extracapsular dendrites of the sympathetic 
cells, their non-medullated neurites, and the collaterals and ter- 
minal portions of the preganglionic fibers before the latter pene- 
trate the cell capsules to give rise to the subcapsular nets. 
Our knowledge regarding the terminations of preganglionic 
fibers in the cranial autonomic ganglia is, with the exception of the 
ciliary, less complete. In the ciliary ganglion pericellular nets 
under the capsules have been observed by a number of investi- 
gators. Michel (94) and Kdlliker (’94) were the first to call 
attention to their presence following the study of Golgi prepara- 
tions of mammalian ganglia. Recently Sala (10) and v. Len- 
hossék (’10), working with the Cajal silver nitrate method, have 
been able to secure excellent demonstrations of these end nets in 
the ciliary ganglia of man. That they are present also in birds 
has been shown by v. Lenhossék (710, ’11) and the writer (Car- 
penter 711), both of whom found, however, that in this group 
another form of termination of the preganglionic fibers occurs in 
the ciliary ganglion. This is the ‘‘ calyx” ending and its modifica- 
tions. Endings of this type have been seen also in the ciliary 
ganglion of reptiles by v. Lenhossék (11a). 
The histology of the remaining autonomic ganglia in the head 
region has received comparatively little attention from investi- 
gators. 
Original descriptions of the cellular elements of the sphenopala- 
tine ganglion are to be found, as far as I am aware, in three papers 
only, and in but one of these are the terminations of preganglionic 
fibers mentioned. The observations of Retzius (’80) on teased 
preparations of the ganglion taken from the sheep and cat fur- 
nished for a long time the only source of information regarding 
