| Prenatal roentgenogram of conjoined quadruplets. |  |
| Pygopagus female twins. infants joined by sacral areas, each of which was the site of a spina bifida. External genitalia were partially fused, and common vaginal and anal orifices were divided by septa separating the two orifices of the two twins. Bladders and all organs were duplicated except the kidneys, of which there were only three. |  |
| Ischiopagus twins. Lower abdominal aras are fused and extremities consequently displaced laterally. Only one pelvis is present, associated with single normal external genitalia, the latter located between right leg of left twin and left leg of right twin. the legs are normal except for clubfoot. Opposite legs are fused into a single composite limb. Viscera of one was in situs inversus position. Aortas were fused. The heart of one twin was hypoplastic and circulation through that twin was in reverse direction through arteries and veins. |  |
| Monocephalus diprosopus: partial duplication of frontal region and nose. |  |
| Monocephalus diprosopus: Partial duplication of frontal region, nose and palate with increase in width of mouth. |  |
| Monocephalus diprosopus: widening of frontal region with duplication of mouth and nose, harelip and cleft palate. |  |
| Monocephalus diprosopus: Duplication of face with a common median orbit. |  |
| Twin pregnancy terminated 18 weeks after last menstrual period with one fetus measuring 1cm, the other 15 cm. This indicates a difference of approximately 12 weeks' gestational age. |  |
| Twin pregnancies with one normal and one severely malformed infant. Abnormal twin with multiple anomalies including renal agenesis and absence of lumbar and lower thoracic segments of the spine. |  |
| Thoracopagus twins. Male twins joined by thorax and upper abdomen. Umbilical cord contained four arteries and two veins. Hearts and livers were joined and only partially duplicated. Gastrointestinal tracts were separate. |  |
| Monochorionic monoamniotic twin pregnancy resulting in abortion because of cord entanglement. |  |
| Craniopagus twins. Median parietal area of right twin is united with right frontoparietal area of left twin. |  |