1890 - 91 .] Alexander Bruce on a Human Cyclops. 
417 
and red nucleus were both present, but the crustal portion of the 
crura cerebri was quite absent, and with it, therefore, all indication 
of the pyramidal tracts. 
The contents of the median eye were removed, and, after harden- 
ing, cut into transverse vertical sections. These revealed the pre- 
sence of two rudimentary eyes in which the lens, the retina, and the 
choroidal pigment layer could be more or less distinctly made 
out. The appearance is shown in PI. III. The retina presented a 
most remarkable appearance. In the mesial plane it was found in 
an extraordinarily convoluted condition, so that it had assumed in 
places an almost tubular structure. This is indicated in the middle 
of the figure. There was no doubt, however, that this was really 
composed of retinal elements and not of a Schneiderian membrane, 
as was suggested to me, for every here and there a perfectly 
distinct retinal structure could be made out. There can be little 
doubt, I think, that the optic vesicles in their forward growth had, 
as it were, lost their way, and grown partly along the mesial 
plane, and partly laterally towards the two eyes. The two eyes 
were embedded in a somewhat fatty connective tissue, in which 
could be found indications of the lachrymal gland. Internal 
to the lenses on either side was a small nodule of cartilage whose 
origin was somewhat doubtful, but which probably represented 
an attempt to form some of the bones of the nose. There 
were large haemorrhages in various positions external to the 
choroidal pigment, and amongst the convoluted folds of the retina 
was a granular substance, in all probability formed of vitreous 
humour. 
Sections at posterior levels to the above demonstrated the exist- 
ence of several of the ocular muscles — the external, inferior, and 
superior recti being quite easily recognised. 
The optic nerve was single, and presented on transverse sections 
a convoluted structure containing elements closely resembling those 
seen in the retina. 
DESCRIPTION OF THE SKULL. 
I. Base of the cranial cavity (fig. 10). — The presphenoid bone 
and the ethmoid were completely absent, but in the middle line, 
in their place, was a foramen bounded {a) laterally by the two 
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