294 DISEASE IN WILD MAMMALS AND BIRDS 
This is obviously a traumatic malformation and 
forms a relatively contracted pehds. The delivery of an 
adult fetus is impossible. 
Cape Hyrax {Hyrax capensis). Impossible labor due to malforma- 
tion of the pelvis. This animal died as the result of shock and exhaus- 
tion of labor. She was pregnant of two fetuses, one of which was 
extracted manually by the keeper but was dead at birth. Twenty-four 
hours later the animal was found dead. On autopsy there was present 
a fully developed fetus in the right cornu, the head just above the pelvic 
inlet. The left cornu was large and boggy. The myometrium of the 
right side was so thin as to be almost transparent. On examining the 
bony pelvis the reason for the dystocia is at once apparent. The sacrum 
is tilted to the right, and the body of the left ileum is bent sharply to 
the right, the pelvic inlet being obliquely contracted, the right oblique 
diameter being 16 mm. while the left is 23 mm. 
The pelvic obliquity made the birth of a full sized 
fetus impossible, the one delivered being under 
developed. The myometrium was evidently stretched 
almost to the point of rupture when death occurred. 
Obstruction to the birth canal by abnormalities in 
the soft parts, such as muscular rigidity, edema, or 
inflammation, tumors, atresia or developmental defects 
are occasionally seen by veterinarians but have not been 
encountered here. 
Dystocia from uterine displacements are uncommon 
except such as may depend upon the failure of support 
by the abdominal wall, since this is the principal support 
of the organ especially when gravid. Hernia or hys- 
terocele is known and anteflexion has been seen., 
Torsion, a rare human condition, is not uncommon in 
lower animals probably due to the loose dependent 
position of the pregnant cornua, attached only to the 
pelvic walls by slender inactive suspensory ligaments. 
A case may be reported, not originally described. 
Canada Porcupine [Erethizon dorsatus dorsatus). Obstructed labor. 
This animal died from exhaustion due to an impossible labor. On 
autopsy the abdomen contained a moderate amount of clear serous 
fluid with one small blood clot. The right uterine cornu was distended 
with a fetus to about the same diameter as the uterine body. This cornu 
