682 THE AMERICAN NATURALIST. | [Vor. XXXV. 
drawings are tracings made by running a pencil around the outlines 
of the feet and hands. The right hand is entirely normal. The 
left hand varies as to the little fingers, there being two digits. A 
careful manipulation of the palm showed that there is a single meta- 
carpal at the base, and distally two digits, each with three bones ; 
the bones are entirely separate, though the skin grows across between 
them on the level of the proximal joint. Both of the feet are six- 
toed, the ulnar digit in each being doubled. This doubling was 
found, by feeling through the skin, to begin with the digit, the meta- 
carpal being single. The left foot bears a lump on the outside at 
the base of the outer digit, seemingly due to an irregularity connected 
with the variation presented by the toes. I was told that it had 
been there from before the time of fitting the first pair of shoes. 
There was no knowledge of a similar condition of the digits in the 
family ; the grandparents were personally known to the young man 
and nothing like it had been remarked among his relatives. 
The case appears to fall in the class of cases noted by Bateson 
(“ Materials for the Study of Variation," p. 345) as among the com- 
monest forms of polydactylism, in which there is an extra minimus, 
the metacarpals and metatarsals being normal. H. L. OSBORN. 
s. Pedigree Mouse Breeding. — V. Guaita has bred white and 
walzing mice through seven generations. There has been a loss of 
fecundity, due to too close inbreeding. Tables are given showing 
the ancestry of about three hundred mice of varying colors. The 
author does not make sufficient use of his data. The most striking 
fact is that when pure-bred white mice were crossed with pure-bred 
walzers (chiefly black and white), all of the twenty-eight progeny 
were gray, or like a house mouse, and none were walzers. When 
these were bred together, nine color classes at once appeared, includ- 
ing albinos and walzers, as well as grays and gray-blacks. If the 
results of breeding in the later generations are compared with what 
one should expect from Galton's law of ancestral inheritance, it 
results that the albinos appear unusually stable and prepotent. On 
the other hand, the walzing condition seems to be unstable and to 
be less potent than normal. 
! Von Guaita, G. Zweite Mittheilung über Versuche mit Kreuzungen von vet 
schiedenen Hausmausrassen, Berichte d. maturf. Ges. Freiburg, Bd. xi, Heft 2, 
pp. 131-138, 1899. 
