VIVIPAROUS FISHES OF THE PACIFIC COAST. 
465 
SUMMARY OF CONCLUSIONS. 
1. Copulation takes place in June or early July. This statement is based on the 
fact that the testes of the male are very much enlarged at this time and on the fact that 
the ovaries from now on are filled with spermatozoa. The act of copulation has not 
been observed. 
2. The secondary sexual differences are considerable — among them may be men- 
tioned a small gland or bag on either side of the anal of the male. From it extends a 
papilla forward to beyond the anterior margin of the fin. 
3. The spermatozoa have a long rod-shaped head in place of the globular one 
usual in fishes. 
4. The spermatozoa remain dormant in the ovary till December, when they become 
exceedingly active. 
5. The eggs mature and are fertilized between November 1 and February 1, the 
largest fishes maturing the eggs earliest, the next in size a little later, and the 
smallest individuals last. 
6. Those spermatozoa not utilized in fertilization remain in the ovary for several 
weeks longer. They are finally eaten by the larvae when the digestive tract of the 
latter has been sufficiently developed. 
7. During the early stages of gestation the females remain in shallow water; 
males are then rarely seen. Later they become scarce, but near the time the young 
are freed and shortly afterwards they are again found in shallow water. 
8. The largest ovarian eggs measure about 0-3 mm. in diameter. During the 
process of maturation the egg contents shrink to a diameter of 0*2 mm., or to less than 
one-third of its maximum size. 
9. The egg of this fish ( Cymatogaster aggregatus) is 130 times smaller than the 
normal fish egg, which has an average diameter of 1 mm. 
10. This small size is largely if not entirely due to the nouformation of deutoplasm. 
11. The egg is fertilized while still in the follicle. Some sections show the extru- 
sion of the second polar globule and the presence of the male pronucleus in an egg 
still surrounded by the cells of the follicle. The latter have begun to degenerate. 
12. The development begins after the egg has been freed from the follicle. Eggs 
with 1, 2, 4, 8, and 16 cells, as well as many later stages, were found free in the ovary. 
13. Neither the developing eggs nor the young are in later stages at any time con- 
nected with the parent, nor is the position of these in relation to the ovarian structures 
a fixed one. 
14. The duration of gestation is probably five months and the number of young 
from 3 to 20, according to the size of the parent. In less than a year after birth the 
young are gravid. % 
15. The food of the young is supplied by the epithelium of the ovary. The cells 
enlarge and become clear, when they collapse, their contents are emptied into the 
lumen of the ovary, and the framework of the cells soon follows. When the intestine 
begins its work the spermatozoa serve as part of the food. The ovary at no time 
was observed to contain more fluids than the peritoneal cavity. (In other species con- 
siderable fluid is sometimes present.) Before the development of the alimentary tract 
the ovarian fluid is probably appropriated by a process of iutracellular digestion on 
the part of the epidermal cells. 
F. C. B. 1892 30 
