MAMMALS OF MINNESOTA. 251 
.extends a prominent ridge diagonally across the parietals to 
the median crest of the supraoccipital. The combined width 
of the parietals is 1.40; two large foramina passing into the 
squamosals at the point of greatest width just behind and 
medianly from the zygomatic process of the squamosals. The 
squamosals are long and narrow, measuring 1.40; the zygomatic 
process being nearly horizontal and only slightly curved at the 
very end. ‘The interparietal is so small as hardly to be no- 
ticed. The skull is flat behind, the supraoccipital being 1.50 
wide and but | high. The par-occipital processes are moder- 
ately prominent and nearly vertical. The foramen magnum 
is nearly 0.60 wide and is lemon-shaped. The premaxillary is 
very large, 0.80 long, and sends up two very large fiat plates 
which incline backward and outward. The opening of the 
nares is thus an inverted truncate triangle. The premaxillary 
extends beyond the nasals considerably. The main portion of 
the maxillary seen from the side is nearly an isosceles triangle; 
the palatal portion is small and ridgy; the infra-orbital foramen 
is immense, leaving two slender columns to support the zyy- 
oma. The palatal is greatly reduced, the last molar being entirely 
back of the palate. The molar series are inclined to each 
other at an angle of 80°; the outer margins if extended for- 
ward meeting at the incisor ora little beyond. The malar is 
1.40 long and greatly expanded anteriorly while its posterior 
end is knobbed and inflexed. 
The basisphenoid is 0.55 long, and its pterygoid processes 
are short but prominent and soldered on to the bulle which are 
prominent and large. The basioccipital is nearly 0.60 long 
along the median line. The lower jaw is massive; the angle of 
the mandible being infiexed, making a large shelf on either 
side. The condyle with its ascending ramus is blunt and short. 
while the coronoid process is but an inconsiderable spur on the 
front edge of the ascending ramus. Length of mandible 2.80; 
hight of ascending ramus 1.30; length of molar series 1.11. 
The pattern of the molar crowns seems, at first, very uniform, 
but a more careful study shows considerable variation. There 
is an outer and inner enamel layer forming a double wall about 
the tooth when worn. The size and general contour of the 
teeth are alike in all of the sixteen teeth, but various minor dif- 
ferences occur. In general each crown consists of two opposite 
semilunes united in the middle; each semilune consists of an 
outer and inner enamel wall, and these may be parallel or the 
inner one may be folded upon itself. In some cases, between 
