78 BULLETIN OF THE 
internal limiting membrane; the inner reticular layer (called by him 
the neurospongium), and scattered in this the ganglion cells ; the inner 
nuclear layer (called by him the ganglion retin); the rudiments of 
the rods and cones; and the radial fibres. Krause’s remarks on the eye 
of Myxine are interesting. He (86, p. 19) says: “Sein Auge würde 
zu den perotischen rückgebildeten, wie das von Proteus anguineus 
zu rechnen sein, und man kann die rudimentür entwickelte Retina 
deshalb nicht zur Construction phylogenetisches Aufbauten benutzen." 
It appears to me that the most interesting fact concerning the Myxi- 
noid eye, at least from a comparative point of view, is the entire ab- 
sence of pigment in it. I may here say that I have made some sections 
of the eye of a member of this family found at Monterey, Cal., and 
named by Lockingtou (78, p. 793) Bdellostoma stoutii, and can con- 
firm the statements made on this point by all other observers. I have 
so far found no trace of pigment in the eye. The proximal layer of 
the primitive optic vesicle remains distinctly cellular throughout life, 
as always stated, but no pigment appears either in it or in the meso- 
dermal tissue immediately surrounding the eye. If, as seems certain 
with the rudimentary eyes of the three forms that we have been consid- 
ering, an increase of pigment is an incident. to the gradual diminution in 
functional importance and structural completeness, I can see no very 
satisfactory explanation for the absence of pigment in the Myxinoid eye, 
if we are to suppose, as I take it for granted we must, that it too is 
the result of arrested development. 
Wyman (54, p. 395; '54*, p. 18; see also Putnam, ’72, pp. 18, 19) 
has made us acquainted with the eye of Amblyopsis spelæus as far as he 
was able to with the methods of morphological investigation of his time. 
And it is altogether probable that all he has made known coucerning 
this species holds good for Typhlichthys subterraneus, since the two 
forms are so nearly alike that systematists are not fully agreed that 
they should be considered as separate species. 
According to Wyman, the eye of Amblyopsis has “a sclerotic coat, 
a choroid coat, a layer resembling the retina, a lens, and a nerve.” 
His notes, published by Professor Putnam, give somewhat more of de- 
tail as to the structure of these several parts. He says: “ Under the 
microscope, with a power of about twenty diameters, the following parts 
are satisfactorily made out: . . . 2d, a layer of pigment cells for the 
most part of a hexagonal form, and which were most abundant about 
the anterior part of the eye; 3d, beneath the pigment a single layer 
of colorless cells, larger than a pigment cell, and each cell having a 
, E) I e 5 e 
