120 JOHN BEARD. 
Seconp SrcmentaL Nerve—OratHaALmMicus Prorunpvs, 
Crurary GANGLION, AND Raprix Lonea. 
A good deal of confusion exists as to the actual nerve com- 
ponents of this segment. 
Marshall! regards the motoroculi as the main stem of the 
ciliary ganglion, and attributes to it the character of an anterior 
and posterior root. In Marshall and Spencer’s? paper the 
ophthalmicus profundus is also classed as part of this segment. 
Schwalbe’ had previously shown that the ciliary ganglion was 
really the ganglion of the posterior root of this segment, a 
demonstration which Marshall confirmed embryologically. 
Following on and extending these discoveries Van Wijhe 
recognised the most important component of this segment in 
the ophthalmicus profundus, which he classed as the posterior 
root of the segment. While accepting to a certain extent 
Van Wijhe’s view, the writer feels bound to admit that from 
Van Wijhe’s researches alone, the matter does not stand in a 
very clear light. 
Here, as in other cases, Van Wijhe’s preconceived notions 
as to the correspondence of the roots of cranial nerves to those 
of spinal nerves, interfered with the proper interpretation. 
Marshall first gave an account of the development of the ciliary 
ganglion; this account Van Wijhe added to, but it is still by © 
no means complete. And although the development of no 
cranial ganglion is easier to follow and no fusion with the epi- 
blast more obvious than the development and fusion of the ciliary 
ganglion, this fusion has never before been figured, and Van 
Wijhe’s earliest stage figured (fig. 31, g/. c, op. cit.) is a stage 
at which the ganglion is in great part separated from the skin, 
and in which the ophthalmicus profundus which runs from the 
1 Marshall, “Segmental Value of Cranial Nerves,” ‘Journ. of Anat. and 
Physiol.,’ 1882. 
2 Op. cit., p. 29. 
3 Schwalbe, ‘ Das Ganglion Oculomotori.’ 
4 Marshall, “‘ Head Cavities and Associated Nerves, &c.,” ‘Quart. Journ. 
Micr. Sci.,’ 1880. 
SS 
