68 BULLETIN OF THE 
they form a regular row through the whole length of the outer member 
(Fig. 22, c). They are mostly confined to the outer members, but in 
some rods a single one of unusual distinctness is found in the inner 
member, 
I now pass to the least developed and most degenerate eyes. Perhaps 
the specimen most interesting in this respect is the one shown in 
Figure 6. In this the lens is entirely absent, a continuation of the 
pigment layer of the retina extending without break entirely over the 
space that this structure should occupy. The series of sections of this 
eye is complete, and every section is as perfect as the one from which 
Figure 6 was drawn; so there can be no possibility that the absence 
of the lens is due to artificial causes, or that an error in observation 
has been made. I should add, also, that I have an equally complete 
series of sections of the other eye of the same individual, and this shows 
the same structure in every particular. Over a portion of the outer. 
moiety, the pigment is disposed in a double layer (Fig. 7, pig.’ and pig."). 
The outer of these layers is more directly continuous, both in thickness 
and direction, with the pigment layer of the retina. The inner layer 
presents a considerably thickened mass, pig.", irregularly lenticular in 
form. From the appearance shown in this figure, one is tempted to 
regard this pigment mass as a remnant of the ‘lens, the thinner portion 
of the layer at its edges, which connects it with the pigment layer of the 
retina, representing the iris. It is very doubtful, however, if such is 
the case. With such an interpretation the outer pigment layer (pig.!) 
would seem to represent the inner layer of the cornea; and this would 
afford an explanation, not obvious otherwise, of the continuity of the 
layer over the pupil. But there are several difficulties in the way of 
these convenient interpretations. In the first place, the pigment mass 
under consideration is found on examining the entire series of sections 
to be very irregular in form, and, as shown in Figure 6, to become con- 
fluent with the outer pigment layer (pig.!) in some portions of the eye; 
in the second place, as is shown in the figures, and has already been 
mentioned, the outer layer is directly continuous with the pigment layer 
of the retina, which of course it should not be if it belongs to the 
cornea; and, in the third place, the inner layer of the cornea is itself 
present and not pigmented (Figs. 6 and 7, ern.). 
Concerning the condition of the retina in this eye I speak with con- 
siderable hesitation, because of a fear that its peculiarities may be due to 
artificial causes. I should say, however, that the specimen was hard- 
ened in chromic acid, and that all the tissues around the eye are well 
