+----------------+----------------+---------------+ | M2W2 1 white. | MmW2 2 white. | m2W2 1 white. | | M2Ww 2 blue. | MmWw 4 white. | m2Ww 2 white. | | M2W2 1 black. | Mmw2 2 black. | m2w2 1 black. | | | | Totals: White ten-sixteenths; black | | four-sixteenths; blue two-sixteenths. | +-------------------------------------------------+ The relation between the calculated and the actual percentages is as follows: White + black specks in females: calculated, 62.5; actual, 57.5. Black: calculated, 25; actual, 22.1. Blue: calculated, 12.5; actual, 20.4. That the agreement is not closer must be attributed to the fact of small numbers and the premature death of many of the chicks, in consequence of which their adult plumage colors were not fully revealed. Also, many "blue" chicks produce white adults with black specks in the plumage. It is to be observed that this explanation calls for a special mosaic (blueing) factor, but this mosaic factor brings about a blue plumage only when the "white" factor is diluted, _i. e._, heterozygous. In the next generation (pen 733) I mated 2 blues together. This mating is generally regarded as a unifactorial one (producing gametes _WM_, _wM_) and to give in every 4 offspring 1 black, 2 blue, and 1 white. I obtained the expected 50 per cent of blues, but always an excess of blacks and a deficiency of whites (49:35:16, respectively). This result is doubtless due to the accident that a large proportion of the chicks were described young, for it appears from my records that some blues become white when older and some "blacks" are certainly _blue-blacks_. The deficiency of whites becomes an _excess_ of whites in the adult stage. The whites obtained from the blues are usually, but not always, splashed with black spots. B. SPANGLING. As is well known, hybrids between black fowl and White Leghorns are usually white with black patches in the females, while their brothers are mostly entirely white. This "spangled" condition is a heterozygous one just as truly as the "blue" condition is. When a splashed hen is mated to her white brother a certain proportion of the offspring are splashed again, _i. e._, one-half of 50 per cent or 25 per cent, that being the proportion of heterozygous females. Actually in 150 offspring 19.4 per cent were splashed and 18.6 per cent black, while 62 per cent were recorded (largely from unhatched chicks) as pure white. The splashing reappears in about the expected proportion of cases. In my pen 633 I take the spangled females to form gametes _WS_, _Ws_, _wS_, _ws_, while the male seems to form gametes _Ws_, _ws_; _S_ being the spangling factor. Then [♀ _WS_, _Ws_, _wS_, _ws_] × [♂ _Ws_, _ws_] gives the combinations shown in table 65. TABLE 65.--_Combinations in zygotes of the second hybrid generation of the spangled strain._