246 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
which were examined, 204 were females and 146 males. The females 
averaged 4.05 inches, the males 3.67 inches in length. 
These fish breed during the spring and early summer, and doubtless 
some of them throughout the summer. During the first week in April 
the common silverside (JZ. men7dia) was found full of spawn at More- 
head City, N.C. They spawn on the sand and in the sedge in shallow 
water close to shore. 
In a brief paper,* published nearly twenty years ago, Ryder gave 
some interesting observations upon the eggs of the silversides which 
he called Mentdia notata. He said: 
The mature eggs of Menidia notata measure about a line in diameter, and are 
covered with a thick, strong egg membrane. When first taken from the parent fish, 
the germinal matter of the ovum is spread mainly over the surface of the vitellus, 
and in the latter a number of highly refringent oil globules of various sizes are 
embedded. In the space of ten hours the batch of ova studied by the writer had 
the germinal disk independently of impregnation. 
Probably the most striking peculiarity about the ova of Menidia is the garniture 
of threads which are attached to one pole of the egg, covering a very small area of 
insertion on the outer surface of the egg membrane. There are four of these fila- 
ments, and when the eggs are first emitted they are coiled around the egg membrane 
externally in a spiral manner. Very soon after oviposition they commence to uncoil 
from around the egg, and when a number are stirred or shaken about in a small 
dish they soon become entangled together so as to hang together in bunches or 
strings. These threads are about eight times the length of the diameter of the 
ovum, and are apparently composed of the same tough material as that which enters 
into the formation of the egg membrane itself. In the immature condition, and 
when the ovarian egg is still far from full grown, I find the threads present on the 
outside of the zona or membrane, closely adherent to the latter. In this condition 
the membrane is relatively thicker than in more mature eggs, and the nucleus is 
quite conspicuous at the center of the immature vitellus. 
The filaments at the point of attachment to the egg membrane are somewhat 
enlarged, but have no bulbous base as in the case of those found on the ova of the 
silver gar. The egg is heavier than sea water, the oil drops embedded in the yolk 
seeming to have no tendency to buoy them up. 
* * * * * * * 
The eggs being taken at night renders it possible that the species is a nocturnal 
spawner, while the singular threads or filaments may be the means by which the 
parent fish is enabled to suspend its ova to some fixed support in the water as 
they are emitted from the oviduct. This might be accomplished by the female while 
the eggs were expelled by simply passing her body over the stems or leaves of 
marine plants in her vicinity. This affords an explanation of the remarkable 
threads which are attached to and at first encircle the egg. We can not escape the 
conclusion, at any rate, that these threads are of the nature of a protective con- 
trivance either to suspend the eggs to foreign objects or else to entangle them 
together in masses, such as we find to be the case with the eggs of the silver gar, 
where the filaments are, however, scattered over the whole surface of the egg. 
Professor Ryder noted that a full-grown female of this species would 
not yield more than 300 eggs; but in this respect, as well as in regard 
to the number of filaments, the observations of Prof. W. J. Moenk- 
*On the thread-bearing eggs of the silversides (Menidia), by John A. Ryder (Bulletin of the U.S. 
Fish Commission 1883, 193). 
