MONSTROSITIES 207 



In the xyphopagus, reduction with the chain saw might be 

 tried ; in the sternopagus, an attempt to remove a head, neck 

 and fore legs is indicated. When this is followed by traction 

 on the remaining head and fore limbs, extraction as far as the 

 hind parts might succeed and further division or embiy- 

 otomy finish it. 



Polymelus. — Although this monstrosity does not, as a rule, 

 cause dystokia, the supernumerary limbs might interfere with 

 expulsion. With regard to the differential diagnosis, twins 

 alone can be considered. Embryotomy in these cases is mostly 

 crowned with success. 



Synkephalus and dipygus may give cause to difficulties in a 

 posterior presentation. 



