DICHOTOMY. 127 
cases of this malformation. A much commoner con- 
dition is to find the abnormal limb projecting posteriorly 
between the normal legs. In such a position the two 
legs are as a rule fused together near their attachment 
to the trunk, but may retain their individuality in the 
distal segments. Such a specimen is sketched in fig. 
71. It isa lamb with a supernumerary pair of confluent 
hind limbs, as shown by dissection, projecting from the 
Fic, 71.--A Lamb with coalesced supernumerary pelvic limbs, 
(After Gurlt.) 
pelvis. In this case the nether opening of the alimentary 
canal is double also. 
A much more obvious case than this is represented 
in the chick (fig. 72). For some reason or other 
supernumerary legs are very common in fowls, ducks, 
geese, pheasants, and lambs. 
In many cases posterior dichotomy of the axis may 
be indicated by one limb only, the other undergoing 
suppression. 
