MoxsrnosiTiEs. 417 



which a pseudenceplialian monstrosity {Perocephalus pseiidocephalns , 

 Gurlt) gave rise to dilliculty iu birth. 



Double-headed (Monosomian and Sysomian) Monstrosities. 



The occurrence of double-headed monstrosities is more common, 

 perhaps, than any other anomaly ; they are observed more particularly 

 in Ruminants, though instances are recorded of their appearing in the 

 Pig, and even in the Cat species. 



We have collected reports of some three dozen cases, the large majority 

 of which refer to this anomaly in the Calf, and not one to the Equine or 

 Asinine species. Only two of these cases appear in English literature. 

 We have alreadv shown, in classification of monstrosities, the kind 



Fig. 122. 

 Sy30mi.\n Mo.vstrosity : Dicephalus bkollis (Gublt). 



and degree of division there exists between the heads, and we have 

 only now to deal with this anomaly from an obstetrical point of view. 



It may bo obsened that many of these creatures have been born 

 alive, and have continued to live for some time. Canu mentions a 

 double-headed Calf which survived its birth fifty days, and Bert gives 

 a good description of another which he examined when it was fifteen 

 months old ; but in the latter instance the anomaly was limited to the 

 lower part of the head, the jaws only giving evidence of duplicity. 



The existence of this anomaly renders birth more or less difiicult, or 

 even impossible, according to the size of the heads, their point of junc- 

 tion — whether at the face or cranium, or towards tlie neck, and also 

 according as the presentation of the fcttus is anterior or posterior. In 

 very many of the cases recorded, the mother died or had to be killed, 

 while in others birth occurred without assistance and with but little 



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