13 



with the locality, but it may be safely said that in this State 

 the generative products ripen during the tirst year. In the 

 siunmer of 1U06, oysters in Calcasieu Tass, which were not more 

 than eight months old were practically all spawning, although 

 the amount of ripe sexual elements was small in each ease. 



The number of eggs discharged by a single female is natur- 

 ally dependent on its size. It has been estimated that an oyster 

 of average size produces 16,000,000 eggs in a year, while a very 

 large individual may produce as many as 60,000,000. The sper- 

 matozoa, being exceedingly minute, are present in the milt in 

 inconceivable numbers. 



Since there are so many chances that the eggs and sperma- 

 tozoa will not meet in the water, the reproductive powers of an 

 oyster bed are not nearly so great as are represented by the re- 

 productive elements discharged l>.y the breeding oysters. Neither 

 the eggs nor sperms live long after they have been dischargd 

 from the body of the parent; so if fertilization is to take place at 

 all, it must be accomplished soon after the sexual products are 

 tlischarged. Even when the eggs and spermatozoa do meet and 

 fuse, the dangers which must be met by the young are so numer- 

 ous that the chances are that only a very small percentage of 

 the fry will become permanently attached and go on with their 

 development. 



DEVELOPMENT OF THE OYSTER. 



By mixing the eggs taken from the reproductive organs of a 

 female oyster with the male reproductive cells it is an easy 

 matter to bring about their union in any small dish of clean 

 sea water: and their development may be followed under a 

 microscope. •- 



Some fifteen minutes after the ^(sfxfi have been fertilized 

 (Plate II. Fig. 1), they will be found to be covered with the 

 male cells. In about one hour the ef^g will be found to have 

 changed its shape and appearance. It ha.s now l)ecome spherical, 

 and the clear central portion — the germinative vesicle — is 

 no longer visible. In a short time a small transparent point 

 makes its appearance on the surface of the o\:cr^ and increasinir 

 in size, soon forms a little transfiarent knob — the pole cell. 



A second nole 'cell is snon afterward given off. and the egg 



