WYMAN — PENOBSCOT FIELD MOUSE 
165 
4 contained the greatest number of variates, thus being the mode. The 
indices of three of the specimens of shaitucki fall into this class, three 
into class 5 and one falls into class 6. This constitutes quantitative 
proof that the audital bullse of M. p. shattucki are not more globular 
than the average bullae of M. pennsylvanicus. 
PALATINE FOKAMINA 
The palatine foramina of meadow mice vary greatly in size and shape. 
Many are seen in skulls collected from various places which appear 
to be as broad as or broader than those of M. p. shattucki, especially 
in large skulls such as those of the Grand Manan series. The length 
and greatest width of the palatine foramina of eight skulls of shattucki 
and of 103 skulls of pennsylvanicus were measured with calipers. The 
dimensions of those of shattucki range from 4.57 by 1.35 to 6.10 by 
1.56 mm. The width of the foramina of pennsylvanicus run up to 1.79 
mm. The average dimensions of the Grand Manan series are 5.89 by 
1.52 mm. The expression ‘‘bottle shaped’’ is an obscure one to deal 
with quantitatively. This character may best be expressed as an 
index by dividing the length by the greatest width, giving a number 
which would be smaller in the case of more bottle shaped foramina. 
This was done for each specimen measured and the results were grouped 
into eleven magnitude classes, class 5 constituting the mode. Of the 
indices of M. p. shattucki, three fall into the mode, three into class 6 
and one each into classes 3 and 4, proving quantitatively that the pala- 
tine foramina of shattucki are not broader in proportion to their length 
than the average foramina of meadow mice, and hence cannot be con- 
sidered more bottle shaped. 
TAIL LENGTH 
The tail length of the new subspecies is described as ranging from 
54 to 62 mm., while the average range of tail length of meadow mice 
is given as from 44 to 46 mm. The recorded measurements, taken in 
the flesh, of 186 specimens of meadow mice range from 30 to 60 mm. 
The tail lengths given in the records with the skins of M. p. shaitucki 
fall well within this range with the exception of two specimens, both 
of which are recorded as 63.5 mm. It is not uncommon to find meadow 
mice with tail length well up to 60 mm., and where only two specimens 
range slightly above this, it seems hardly plausible to base a subspecies 
on such a character. There is a possibility, also, that the records on 
