60 BULLETIN OF THE 
those of Lankester and Bourne, and although he has given no definite 
description of a sclera-matrix in these eyes, yet one may fairly infer 
(cf. 2. ¢., p. 77) his belief in such a matrix, and can find in his figure 
(left side) indications of nuclear structures which easily admit of such an 
interpretation. ‘These (sclera-matrix?) cells I consider to be, in any 
event, the equivalent of what Lankester and Bourne have described as 
“interneural epithelial cells,” the nature of which, it will be observed 
from their figures (Figs. 2, 3) and descriptions, differs considerably in 
Euscorpius and Androctonus. 
But in addition to the considerations presented by Lankester and 
Bourne, there is another objection to the interpretation here proposed, 
which at present I am not able to explain. The direct and apparently 
primitive manner in which the retinal cells are continued into the nerve 
fibres seems to point to a normal rather than an inverted condition of 
the retina. 
In either event, the nature of the lateral eyes in scorpions is deserving 
of further study ; and it will not be surprising if it is found that they 
arise by a process of infolding accompanied by inversion of the retina. 
Grenacher (’78) has given a figure of an ocellus in one of the Phalan- 
gide which indicates the presence of a distinct layer of cells (‘ vitreous ”) 
in front of the retina; and although he has not seen anything of a layer 
behind the retina, these eyes present no more serious obstacle to an origin 
by involution than do most of the hitherto published figures of the eyes 
of spiders. 
The conditions in the eyes of Myriapoda leave more room for doubt. 
Graber, Grenacher, and Sograff are the only authors who have recently 
given them any considerable attention. 
The eyes in Myriapods — aside from Scutigera, in which they are of 
a conspicuously different type — are apparently either monostichous 
(Chilognatha) or so-called diplostichous (Chilopoda). The latter evi- 
dently approach more nearly the conditions found in Arachnoidea, and 
will be considered first. 
Graber (’79, p. 59) claimed their substantial agreement with the ocelli 
of the Arachnoids and Hexapods. While Grenacher’s subsequent work 
has made much of Graber’s description appear illusory, there are still 
some points in which it is probable that Graber has given reliable presen- 
tations of the histological structure. There is, at least, one thing in 
which I believe his observations deserving of more attention than they 
