Monocephalus thoracopagus conjoined twins in a goat

Monocephalus thoracopagus is a kind of attached symmetrical twin in which two nearly complete individuals joined front-to-front in the thoracic region with a single head, fused chests, one or two hearts and two lower bodies. A died female kid goat with one head, four ears, four paired limbs and two more or less complete body was referred to the Veterinary Faculty of the Shahid Bahonar University of Kerman. Detailed dissection was done on it and the progress of the duplication process of the internal organs was studied precisely. In the presented case, the way of the articulation of the ribs to the sterna and the progress of the duplication process in the alimentary canal can support the Spencer's spherical theory, saying that “a group of conjoined twins resulting from the union of two embryonic discs (or incomplete fission in one disc) over a common yolk sac”.