34 
NATURE 
[May 13, 1886 
for March 29, 1886, by Von Henri W. de Graaf, “ Zur 
Anatomie und Entwickelung der Epiphyse bie Amphibien 
und Reptilien,” wherein are described briefly (1) the de- | 
velopment of the epiphysis, and (2) the structure of this 
part in the adult animal in certain amphibia and reptiles. 
An examination by means of sections at once revealed 
the fact that in Hatteria the epiphysis becomes modified 
in a manner more interesting than that found by Von 
Graaf to obtain in Anguis fragilis—the most modified 
form described by him. 
The epiphysis apparently arises as a hollow outgrowth 
from the roof of the third ventricle (region of thalamence- 
phalon), and in both amphibia and reptilia becomes 
divided into two parts—a proximal one remaining in con- 
nection‘ with the brain, and a distal bladder-shaped 
Gish hds 
yy LY, 
Fic. 1.—Longitudinal vertical secti 
from within outwards of the following layers:—(1) a 
layer which is not well marked (x), and which may pos- 
sibly be due to the shrinkage and clinging to the walls of 
the contents of the vesicle, fluid in life; (2) a layer of 
rods (R) embedded in dark brown pigment, the pigment 
being specially developed anteriorly at the part indicated 
by the letter K ; (3) a double or even triple row (IN) of 
nuclei ; (4) a clear layer (M) which scarcely takes stain, 
and may be called the molecular ; and (5) an outer layer 
(EN) of nuclei two or three rows deep. 
This structure will, so far, be seen to correspond closely 
with that of Anguis. 
a Posteriorly a nerve enters the eye, the fibres spreading 
round behind the vesicle; the rods may be observed 
giving off processes from their external ends, which in 
some cases appear to pass right through the layers (3), 
structure—the two becoming in most cases completely 
separated from each other. In Anguzs Jragilis Vou 
Graaf finds that the distal part loses all connection with 
the brain, and develops into a structure resembling a 
highly organised invertebrate eye with, however, the 
important and curious exception that no nerve is present. 
In Hatteria a still more interesting modification takes 
place, the distal portion being, as in Anguis, modified to 
form an eye ; but this, unlike that in the latter, is pro- 
vided with a well-marked nerve. 
Fig, 1 shows the structure of the eye. The whole 
is enclosed in a capsule of connective tissue (C) ; ante- 
riorly a lens (L) is present, composed of cells whose 
nuclei are very distinct. The lens forms the anterior 
boundary of a vesicle, the walls of which are formed 
C.T. 
on of parietal eye of Hatteria punctata. 
| (4), and (5), and in others to be connected in their 
| passage with the nuclei of these layers. 
| However, I hope in a very short time to publish a 
detailed account of the histological structure of the 
organ. . 
The capsule containing the eye is filled posteriorly 
with connective tissue (CT), in which breaks up and 
ramifies a blood-vessel which enters along with the nerve 
(BV). 
Fig. 2 represents somewhat diagrammatically a section 
single and lies exactly in the median line. A depression of 
the skin of the head occurs immediately over the parietal 
foramen, but does not lead down into this, which is filled 
up by a plug of connective tissue (Fig. 1, T, Fig. 2, PT), 
specially dense (D T) around the eye capsule. The nerve 
transverse to the parietal foramen, showing that the eye is" 
