Spermatogenesis of Succinea ovalis, Say

Abstract

AN investigation of the Spermatogenesis of Succinea ovalis, Say., a small terrestrial pulmonate of North America, has revealed the following: 1. Forty chromosomes are found in the spermatogonial divisions, and twenty in the maturation divisions. 2. Typically of all pulmonates so far studied, there are two centrioles, proximal and distal. Early in spermogenesis the proximal centriole penetrates through the nucleus of the spermatid, and with the surrounding intranuclear canal, forms an intranuclear rod in very much the same way as has been reported for certain prosobranchs. 3. Both the head and tail of the spermatozoon have a spiral twist. These spirals go in either a clock-wise or counter clock-wise direction, one type being about as common as the other.