38p FCETAL DYSTOKIA, 



of the cranium (Fig. 83) ; at other times it is bilobular, and the divisions 

 may be either alike or unequal in volume. Not unfrequently the diam- 

 eter of such a tumor in the calf measures more than a foot. The tumor 

 is soft and depressible in parts, hard and resisting in others, owing to 

 the bones of the cranium being altered and separated in places. These 

 bones — and particularly the frontal, temporal and parietal — are, as a rule, 

 considerably deformed and thrown out of their natural direction, and in 

 places so expanded and rarefied as to be i\o thicker than tissue-paper ; 



Fig. 78. 



Skull of a Hydrocephalic Calf: the Cranial Bones are partially destroyed 

 and defective. 



when the internal distention has been very considerable, their borders do 

 not meet as in their normal condition, but are often widely separated, 

 leaving between them vast fontanellae occupied only by a thin translucid 

 membrane — the dura mater — which is in immediate contact with, and 

 adheres closely to, the skin. 



In some instances — especially in the calf — the bones in their upper 

 part do not join at all, and the roof of the cranium, or, rather, of the 

 cranial tumor, is entirely absent (Fig. 79). In other instances, and 

 particularly in the foal, a kind of bony arch extends from the nasal to the 

 occipital bones, in the direction of the saggital suture, with only here and 



Fig. 79. 

 Skull of a Hydrocephalic Calf: the Roof of the Cranium is absent. 



there, on each side, small osseous patches from the parietal or temporal 

 bones, and adhering to the dura mater. 



The tumor is always entirely covered by intact, though sometimes 

 very thin skin, to which the hair is ordinarily attached, and is indeed at 



