36 Mr. E. W. L. Holt on the Ova of Gobius. 
tines one can frequently make out a division into two strands, 
which do not as a rule cross each other, but seem to be merely 
apposed. 
Filaments or processes are known to occur on the eggs of 
many Teleosteans. They were found by Hoffmann* in Gobius 
minutus , niger , and other species, Heliosis chromis , Belone, 
and Bfennius . Eigenmann, in his recent excellent memoir 
u On the Egg-membranes and Micropyle of some Osseous 
Fishes ” t 7 very clearly describes the development of the fila- 
ments in Fundulus . In this form they are developed all over 
the surface of the egg, whereas in our ova the process of 
attachment is confined to what is presumably the micropylar 
region. In Fundulus the filaments, originally arising internal 
to the granulosa, are shown to pass through and, in further 
development, to lie external to it, being “ bent in a more or 
less regular manner first to one side and then to another,” and 
u usually follow the margins of the granulosa cells,” to which 
they are “ correspondingly curved.” 
Eigenmann also notices rivet-shaped processes on the eggs 
of Pygosteus , and from certain phenomena noticed in his 
preparations suggests that “ they are from the beginning 
adhesive.” He describes a layer external to the zona in all 
eggs on which processes are found. Whether such a layer 
exists here I cannot say, nor can I speak with accuracy as to 
the relation of the attachment process to the zona. 
But it seems possible that filaments may be developed in 
this form as in Fundulus and Pygosteus (though confined to a 
restricted area), and penetrating the granulosa in due course, 
so as to lie along the margins of the granulosa-cells, and 
u being from the beginning adhesive,” may have set up with 
each other intimate relationships, resulting in the formation, 
by the adhesion and ultimate fusion of their proximal elements, 
of such a structure as is actually found in the extruded ova 
before us. The distal parts of the filaments, not coming into 
contact with each other, and thus remaining independent, may 
perhaps have extended over a considerable part of the granu- 
losa, and the whole pedicle of attachment is probably everted 
on extrusion of the egg in the same manner as the outer mem- 
brane of the zona in Osmerus , described by Buchholz and 
Cunningham. 
Eigenmann speaks of his u rivet-shaped processes ” in 
Pygosteus as taking a much deeper stain than the membrane 
(external to the zona) in which they are set. Treated with 
* Hoffmann, “ Zur Ontogenie der Knockenfische,” Verhandel. d. J£on. 
Ak. v. Wetenschappen, Amst. Heel xxi. 1881, p. 19. 
t Bull. Mu&. Comp. Zool. vol. xix. no. 2. 
