Few cysts advance to the coiling stage in mutant males. The paracrystalline material of the major mitochondrial derivative is diffuse and irregular in elongating cysts. Individualisation is at least partially completed, but the major mitochondrial derivative does not differentiate uniformly. Paracrystalline body formation is initiated late and randomly in the matrix of the major derivative, rather than at the point of association of the mitochondrial membrane and the axonemal sheath. The organisation of the axoneme is normal.

Mutant males have no motile sperm in the testes.