Page:Popular Science Monthly Volume 81.djvu/374

368 usually these statements are to the effect that the bird's ovary contains "several hundred" ova.

Not only is the absolute number of oocytes large, but it is also very much larger than the number of eggs which any hen ever lays. A record of 200 eggs in the year is a high record of fecundity for the domestic fowl, though in exceptional cases it may go even a hundred eggs higher than this. But even a 200-egg record is only a little more than a tenth of the average total number of visible oocytes in a bird's ovary, to say nothing of the probably much larger number of oocytes invisible to the unaided eye, but capable of growth and development. In other words, it is quite evident from these figures that the potential "anatomical" fecundity is very much higher than the actually realized fecundity. This is true even if we suppose the bird to be allowed to live until it dies a natural death.

An examination of the table in detail indicates that there is no very close or definite relationship between the number of visible oocytes on the ovary and the winter production of a bird. Thus No. 1,367 and No. 3,546 each have about the same number of visible oocytes, yet one has a winter production record 18 times as great as the other. Again No. 71 with the extraordinarily high winter record of 106 eggs has only a little more than one half as many visible oocytes as hen No. 2,067, whose winter production record is only 32 eggs. Again, No. 71 with its 106 record has very nearly the same oocyte count as No. 8,010 with a winter record of zero. In general it may be said that the present figures give no indication that there is any correlation between fecundity as measured by winter production, and the number of oocytes in the ovary. Of course, the present statistics are meager. More ample figures are needed (and are being collected) from which to measure the correlation between actual and "anatomical" fecundity.