+--------+--------------------------+-------+------+-----------+
| Grade | Grade of offspring. | | | |
| of +--+--+--+--+--+--+--+--+--+Totals.|Means.|Regression.|
|parents.|2¼|2½|2¾| 3|3¼|3½|3¾| 4|4¼| | | |
+--------+--+--+--+--+--+--+--+--+--+-------+------+-----------+
| 2⅝ | 2| 3| 2| 5| 5| 1| 1| | | 22 | | |
| 2¾ | | | 2| 4| 1| 8| 2| | | 17 | | |
| 3 | | | | | | | 4| 4| 1| 9 | | |
| 3¼ | | | | 1| | | 3| 1| | 5 | | |
+--------+--+--+--+--+--+--+--+--+--+-------+------+-----------+
|Totals | | | | | | | | | | | | |
| or | | | | | | | | | | | | |
|means, | | | | | | | | | | | | |
| 2.79| 2| 3| 4|10| 6|12|10| 5| 1| 53 | 3.32 | -.53 |
+--------+--+--+--+--+--+--+--+--+--+-------+------+-----------+
TABLE 42.—_Classification of the extracted hooded individuals obtained in
the second generation from a cross between hooded and wild rats._
+----------------+-----------------------------------------------------+
|Grade of hooded | Grade of extracted hooded grandchildren. |
|grandparents. | |
| +--+---+---+---+--+--+--+--+--+--+--+--+--+--+--+--+--+
| |-2|-1¾|-1½|-1¼|-1|-¾|-½|-¼| 0|+¼| ½| ¾| 1|1¼|1½|1¾| 2|
+----------------+--+---+---+---+--+--+--+--+--+--+--+--+--+--+--+--+--+
|♀ -1⅞, | | | | | | | | | | | | | | | | | |
| gen. 2½, | | | | | | | | | | | | | | | | | |
| minus series | | | 2 | | 4| 6| 5| 6|13| 2| 1| 3| 4| 5| 3| 4| 2|
|♀♀ -2, | | | | | | | | | | | | | | | | | |
| gen. 6, | | | | | | | | | | | | | | | | | |
| minus series | | 1 | 1 | 1 | 1| 2| 6| 6| 7| 2| 3| 6| 4| 2| 4| 1| |
|♀♀ -2 | | | | | | | | | | | | | | | | | |
| and -2¼, | | | | | | | | | | | | | | | | | |
| gen. 10, | | | | | | | | | | | | | | | | | |
| minus series | 1| 3 | 3 | 1 |10| 3| 9| 8|14| | 4| 7| 8| 1| 4| 3| 5|
|♀♀ +3, | | | | | | | | | | | | | | | | | |
| gen. 3, | | | | | | | | | | | | | | | | | |
| plus series | | | | | | | | | | | | | | | | 1| 5|
|♀♀ +3¼, | | | | | | | | | | | | | | | | | |
| gen. 5 | | | | | | | | | | | | | | | | | |
| and +3½, gen. | | | | | | | | | | | | | | | | | |
| 6, plus series| | | | | | | | | | | | | | | 1| 2| 1|
|♀ +4¼, | | | | | | | | | | | | | | | | | |
| gen. 10, | | | | | | | | | | | | | | | | | |
| plus series | | | | | | | | | | | | | | | | | 1|
+----------------+--+---+---+---+--+--+--+--+--+--+--+--+--+--+--+--+--+
+----------------+--------------------+----------------------------------+
| | |Total. |
| | Grade of | |Mean. |
| | extracted | | |Mean, uncrossed race. |
|Grade of hooded | hooded | | | |Standard deviation.|
|grandparents. | grandchildren. | | | | |Standard |
| | | | | | | deviation, |
| +--+--+--+--+--+--+--+ | | | | uncrossed |
| |2¼|2½|2¾| 3|3¼|3½|3¾| | | | | race. |
+----------------+--+--+--+--+--+--+--+--+-----+-----+-----+-------------+
|♀ -1⅞, | | | | | | | | | | | | |
| gen. 2½, | | | | | | | | | | | | |
| minus series | 1| | | | | 1| |62|+ .31|-1.20| .98| .49 |
|♀♀ -2, | | | | | | | | | | | | |
| gen. 6, | | | | | | | | | | | | |
| minus series | | |1 | | | | |48|+ .25|-1.59| .97| .44 |
|♀♀ -2 | | | | | | | | | | | | |
| and -2¼, | | | | | | | | | | | | |
| gen. 10, | | | | | | | | | | | | |
| minus series | 2| 4| 1| | | | |91|+ .24|-2.05| 1.18| .24 |
|♀♀ +3, | | | | | | | | | | | | |
| gen. 3, | | | | | | | | | | | | |
| plus series | 3| 2| 3| 4| 2| 1| |21|+2.56|+2.60| .50| .53 |
|♀♀ +3¼, | | | | | | | | | | | | |
| gen. 5 | | | | | | | | | | | | |
| and +3½, gen. | | | | | | | | | | | | |
| 6, plus series| 1| 1| 6| 9| 8| 8| 1|38|+2.97|+3.14| .52| .49 |
|♀ +4¼, | | | | | | | | | | | | |
| gen. 10, | | | | | | | | | | | | |
| plus series | | | 3| 4| 2| 3| 3|16|+3.15|+3.84| .28| .36 |
+----------------+--+--+--+--+--+--+--+--+-----+-----+-----+-------------+
TABLE 43.—_Classification of the extracted hooded individuals obtained in
the second generation from a cross between hooded and Irish rats._
+---------------+-----------------------------------------------------+
|Grade of hooded| Grade of extracted hooded grandchildren. |
|grandparents. | |
| +--+---+---+---+--+--+--+--+--+--+--+--+--+--+--+--+--+
| |-2|-1¾|-1½|-1¼|-1|-¾|-½|-¼| 0|+¼|+½|+¾|+1|1¼|1½|1¾| 2|
+---------------+--+---+---+---+--+--+--+--+--+--+--+--+--+--+--+--+--+
|-1½, gen. 3½ | 1| 5 | 3 | 6 |12|26| 9| 9|10| 1| 3| 2| 2| 1| | | |
|-1⅞, gen. 4 | | 6 | 3 | 4 | 5| 9|14| 8| 1| | 1| 1| 1| | | | |
|+2, gen. 7½ | 6| 6 |12 |11 | 8| 3| 4| 4| 6| 1| 3| | | | | 1| 1|
|+2¼, gen. 2 | | | | | 3| 4| 5| 4|16| 7|16|22|25|29|24|13|33|
|+3, gen. 3 | | | | | 2| | | | 1| 1| 3| 3| 4| 2| 2| 1| 2|
+---------------+--+---+---+---+--+--+--+--+--+--+--+--+--+--+--+--+--+
+---------------+-----------------+--------------------------------------+
| | |Total. |
| | Grade of | |Mean. |
| | extracted | | |Mean, same grade and |
| | hooded | | | generation, uncrossed race.|
|Grade of hooded| grandchildren. | | | |Standard deviation. |
|grandparents. | | | | | |Standard |
| | | | | | | deviation, |
| +--+--+--+--+--+--+ | | | | uncrossed |
| | 2|2¼|2½|2¾| 3|3¼| | | | | race. |
+---------------+--+--+--+--+--+--+---+-----+-----+-----+----------------+
|-1½, gen. 3½ | | | | | | | 90|- .62|-1.31| .61| .48 |
|-1⅞, gen. 4 | | | | | | | 53|- .73|-1.18| .60| .46 |
|+2, gen. 7½ | 1| | | | | | 66|- .94|-1.75| .84| .35 |
|+2¼, gen. 2 |33|14| 8| 8| 6| 3|239|+1.27|+1.80| .90| .75 |
|+3, gen. 3 | 2| 1| 1| | | | 23|+ .95|+2.50| .87| .53 |
+---------------+--+--+--+--+--+--+---+-----+-----+-----+----------------+
TABLE 44.—_F₃ generation produced by extracted hooded rats (F₂
generation) derived from a cross of a hooded rat of the minus series with
a wild rat. (See Table 42.)_
+--------+-----------------------------------------------------+
| Grade | Grade of (F₃) offspring. |
| of (F₂)+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|parents.|-1|-¾|-½|-¼| 0|+½| ¾| 1|1¼|1½|1¾| 2|2¼|2½|2¾| 3|3¼|3½|
+--------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ¾ | 2| 1| 4| 3| 4| 1| 2| 1| | | | | | | | | 1| |
| 2½ | | | | | 1| 1| 1| 3| 2| 2| 1| 5| 3| 6| 4| 3| 1| 1|
+--------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+--------+-------+------+-----------+
| Grade | | | |
| of (F₂)+Totals.|Means.|Regression.|
|parents.| | | |
+--------+-------+------+-----------+
| ¾ | 19 | + .04| .71 |
| 2½ | 34 | +2.06| .44 |
+--------+-------+------+-----------+