Presence of a crystal in the cytoplasm of the male germ cells of the garden dormouse Eliomys quercinus L.

A crystal is present in the cytoplasm of the male germ cells of a hibernator, the garden dormouse, Eliomys quercinus. In another hibernator, the thirteen-lined ground squirrel Citellus tridecemlineatus, such crystals were not found. In the garden dormouse, the crystal is present in the cytoplasm of spermatocytes I and II and of spermatids, after which it is found in the residual bodies. The crystal is usually an ovoid ca 2.4 microns long and 0.75 microns by 1.6 microns when sectioned transversally at its widest region. It is composed of 40 to 80 tubule-like structures, which are 12 nm in outside diameter and have a lumen 8 nm in diameter; the wall is thus ca 2 nm thick. Each tubule seems to be made of two fibrils ca 2 nm in diameter tightly coiled. The tubule-like structures have a zigzag course and are parallel to one another, about 8 nm apart; they are arranged like stacked spoons. Each tubule-like structure consists of two repeating units, one 40 nm long and the other 60 nm. Each unit is inclined to its predecessor at 130 degrees, alternately right and left, thereby giving the zigzag effect. The crystals are present in active and in torpid animals and during normal or induced spermatogenesis; their presence, therefore, does not seem to be dependent on the hormonal status of the hibernator.