DEVELOPMENT AND LIFE HISTORY OF SOME TELEOSTS 
551 
Nothing definite can be said concerning the spawning places of the two species of 
Gobiosoma represented locally, first, because the young under 10 mm in length could 
not be separated, and second, because ripe G. ginsburgi were not taken. Ripe G. bosci 
were taken only in the Mullet Pond where they no doubt spawn, as the larvae were 
present in the same places where the adults were taken. It seems probable, therefore, 
that spawning takes place in the general habitat of the adults. If that were the case, 
then it would follow that G. bosci would spawn only in shallow water along the shores, 
whereas G. ginsburgi would spawn principally in somewhat deeper water (see p. 548). 
DESCRIPTIONS OF THE EGGS AND YOUNG 
Eggs. — The eggs stripped from ripe fish taken in the Mullet Pond were first 
described by Kuntz (1916, p. 423). Since the present investigators have found only 
G. bosci in that pond, it seems probable that the eggs described were of this species. 
The eggs were secured again by the present investigators in August 1930 from fish 
taken in the Mullet Pond. The description of the eggs given by Kuntz is essentially 
correct. The ova when expressed from the female adhere in clumps unless immediately 
separated. The eggs when seen in a mass with the unaided eye are yellowish in color 
and quite opaque. Under the microscope a “bundle” of gelatinous threads with 
small branches are seen to be joined to the egg membrane at a certain point. These 
threads cause the eggs to adhere. Their function no doubt is that of attaching the 
eggs to vegetation or other objects in the water. The eggs are slightly heavier than 
sea water and when placed in a dish of water they sink gradually. 
The mature unfertilized eggs, as observed by us, generally, are slightly elongate, 
but sometimes nearly spherical. The variation in the major axis of five selected eggs 
ranged from 0.637 to 0.675 mm and for the minor axis in the same eggs it was 0.52 to 
0.6 mm. As soon as fertilization had taken place the eggs began to expand and 
became elliptical in shape. In the process of expansion the minor axis retained about 
its former length, for in 10 eggs measured during various cleavage stages it ranged 
from 0.573 to 0.592 mm. The major axis, however, becomes much longer, for its 
range in length in the same eggs ranged from 1.147 to 1.369 mm. Expansion appears 
to be fully completed by the time the first cleavage takes place and thereafter, ac- 
cording to our observations, the egg changes little or not at all in shape. According 
to Kuntz’s figures, eggs with large embryos are more pronouncedly elliptical than 
those in the early cleavage stages (fig. 32). 
When the egg is fully expanded a relatively large perivitelline space is present, 
for the yolk mass occupies somewhat less than half the space within the egg membrane. 
The position of the yolk varies greatly. Generally it lies toward one pole of the major 
axis of the egg and most frequently opposite the pole at which the gelatinous adhesive 
strands are attached. Occasionally, however, it is much nearer the opposite pole of 
the major axis, or it may occupy an intermediate position (fig. 33). 
The yolk mass of the egg when seen under magnification has a greenish-yellow 
cast and it contains many minute oil globules. Due to the opaqueness of the yolk, 
many of the phases in the development either cannot be seen at all or are obscure. 
The processes in the development of the egg are well described and accurately figured 
by Kuntz (1916, pp. 423 to 426, figs. 43 to 50). 
The cells in the early cleavage stages stand out very prominently as round 
elevations. As cleavage advances the fissures become less pronounced and gradually 
the blastoderm becomes circular in outline and sharply differentiated from the yolk 
(figs. 34 and 35). 
154979—38 4 
