Double monsters are pathological deviants from identical twins, in that the embryos are joined in some manner. The embryos may be symmetrically united and developed, or one of the individuals may he arrested in its development. In describing the morphological relationships of the calf of this study, the right and left sides will refer to the animal's right and left respectively. From a superficial examination of this specimen it appears to be a single-bodied calf with two heads, an extra leg with two hooves protruding from the hack a short distance caudal to the vertex of the two heads, and two tails. These facts indicate that there are two animals in this union, hut this indication is not carried out on the ventral surface as there are only four teats and one opening for the umbilical vessels to enter the body.
Proceedings of the Iowa Academy of Science
©1939 Iowa Academy of Science, Inc.
Stiles, Karl A. and Spencer, Collis M.
"A Bovine Monstra Duplica,"
Proceedings of the Iowa Academy of Science, 46(1), 447-449.
Available at: https://scholarworks.uni.edu/pias/vol46/iss1/134