59 



water; males are then rarely seen. Later they become scarce but near 

 the time the young «re freed and shortly afterwards they are again found 

 in shallow water. 



8. The largest ovarian eggs measure about .3 mm. in diameter. Dur- 

 ing the process of maturation the egg contents shrink to a diameter of .1' 

 mm. or to less than one-third of its maximum size. 



!). The egg of this lish, Cymatogaster aggregates, is 130 times smaller than 

 the normal fish egg which has an average diameter of 1 mm. 



Id. This small size is largely if not entirely due to the non-formation 

 of deutoplasm. 



11. The egg is fertilized while still in the follicle. Some sections 

 show the extrusion 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 fol- 

 licle. Eggs with one, two, four, eight and sixteen 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 connected with the parent nor is the position of these in rela- 

 tion to the ovarian structures a fixed one. 



14. The duration of gestation is probably five months and the number 

 of young from three to twenty according to the size of the parent. In less 

 than a year after birth the young are with young. 



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 considerable fluid is 

 sometimes present.) Before the development of the alimentary tract the 

 ovariarn fluid is probably appropriated by a process of intercellular diges- 

 tion on the part of the epidermal cells. 



16. The yolk is a waning structure and can scarcely be taken into con- 

 sideration in accounting for the growth of early stages. 



17. During the whole of gestation respiration is carried on by the 

 osmotic action between the general surface and the closely applied ova- 

 rian structures. When the alimentary tract is opened a current is kept 

 flowing through it and aeration is, in all probability, effected by the ali- 



