22 BULLETIN NO. VII. 
only after birth. An os centrale is found in the carpus. The 
outer or acetabular border of the ilium is almost obsolete, and 
the gluteal and iliac surfaces are confluent. 
The tibia is very long. There is a third trochanter below 
the trochanter major of the femur. The fibula is slender and 
distally united with the tibia, while above, it is united by an 
interosseus cartilage. The hallux or inner toe is wanting, and 
the metatarsals are elongated. 
COMPARISON OF CRANIA OF AMERICAN HARES. 
The skulls of Lepus callotis and of L. californicus are very 
similar. JL. californicus appears to have the mandible more 
slender, with the margin between angle and condyle more 
deeply excavated, otherwise the two species agree quite fully 
and differ from L. timidus var. arcticus and L. campestris in 
the very long and slender nasals, the less strong curvature of 
the crani-facial axis and some other differences. 
The skulls of LZ. aquaticus and L. palustris carry out the 
peculiarities of the ZL. sylvaticus group to anextreme. The 
lower jaw becomes solid and broad. The supraorbital frontal 
processes are fused completely with the skull. The hamular 
process of the zygomas are enlarged, thus giving greater 
security to the glenoid fossa. In both, the maxillary part of 
the inter-alveolary bridge is enlarged rather than the palatal 
portion. The constriction of the nasals just prior to the end 
is also noticeable. 
The differences between the skulls of Lepus sylvaticus and L. 
auduboni are not of avery tangible character,if we may judge 
from Prof. Baird’s figures. The comparison is not facilitated 
by the fact that the skull of the latter figured was evidently 
that of a young animal while that of LZ. sylvaticus is an old one 
with sutures closing and frontal processes united with the 
skull. (See Baird’s Mammals, PI. lviii.) The interparietal of 
the latter is either ignored or has anchylosed with the neigh- 
boring parts. But we know that usually at least this anchy- 
losis does not take place even in old L. sylvaticus. Other 
apparent differences may, probably, be eliminated in like man - 
ner. Baird’s figure of the basis cranii in the one case is in- 
complete but shows the absence of two teeth present in the Z 
sylvaticus. 
