Found in descendants of a four-way cross. Probably extinct. Penetrance is probably not complete, and there may be some loss of homozygotes in segregating generations because of inviability. The mutant mouse resembles Dnahc11^iv but was not tested for allelism with it. Homozygous mutant mice show complete or partial reversal of the viscera as well as a general sickliness and often hydrocephalus (J:306).