296 Maine; agriculturai, e;xperiment station. 19 12. 



these counts do not give the total numbers they do estabhsh 

 minimum vahies. A given ovary certainly does not carry any 

 less than the number of visible ova. 



' A word should be said as to the method of making the counts, 

 and the meaning of the subdivisions of the table. The counts 

 were made in some cases on fresh, and in other cases on pre- 

 served ovaries. There was found to be little difference in the 

 two methods, as regards the ease and accuracy of counting. In 

 making the counts small pieces of ovary were cut off, and teased 

 apart with needles under water and the visible oocytes on the 

 small fragments counted. In delimiting boundaries where a 

 number of small oocytes were closely packed together, a hand 

 lens was used. No oocyte was counted, however, which could 

 not be seen with the unaided eye. In other words the lens was 

 not used to find oocytes which might otherwise be missed, but 

 merely to aid in the dissecting of the material. 



In the oocyte counts given in the table it will be noted that 

 these are grouped into four categories. The first class includes 

 ruptured follicles from which the ova have been discharged. A 

 ruptured follicle which is large at the moment the ovum leaves 

 it gradually shrinks in size and is more or less completely ab- 

 sorbed. On the ovary of a hen which has laid, however, there 

 will always be found a certain number of these discharged 

 follicles not yet absorbed. When such follicles get very small 

 it is exceedingly difficult to distinguish them from small oocytes 

 (i. e., undischarged follicles). Undoubtedly there are errors in 

 classification in this respect in the counts, but for present pur- 

 poses this is not a matter of great importance. If the eye were 

 sharp enough it might perhaps be possible to distinguish a rup- 

 tured follicle for every egg which has ever been laid, since it is 

 doubtful if the absorption is ever so complete as to leave abso- 

 lutely no scar. It is of interest to note that in the counts there 

 is a reasonably close relation between .the follicle count and the 

 record of eggs laid. 



The oocytes proper are divided in the counting into three 

 classes : those i cm. or over in diameter, those between i mm. 

 and I cm. in diameter, and those less than i mm. in diameter. 

 The first of these classes includes the large yolks nearly ready 

 to leave the ovary and pass into the oviduct. They are in pro- 



