A Comparative Study on Tapetum

Abstract

1. Division synchronization being taken as criterion, different cases of tapetum are classified into three types: 1) synchronized type, 2) asynchronized type and 3) intermediate type.
3). In the synchronized type second division takes place and further divisions may also occur. The final form is mostly of the periplasmodium type, with some few exceptions.
3. In the asynchronized type, the first division takes place, but no further divisions. The final form is exclusively of the secretion type.
4. In the intermediate type, two subtypes are distinguishable. In subtype 1, second division takes place as in the synchronized type, and in subtype 2, it does not as in the asynchronized type. In the intermediate type, both periplasmodium and secretion types are observed, and in subtype 1, the periplasmodium type case is found in a greater frequency than the secretion type case, and in subtype 2 the two cases are found in the reversed ratio.
5. It is concluded that the tapetum which is of sporogenous cell complex origin would be the product of counteractions between the original character retaining tendencies and the tendencies converting toward somatic nature. The apparent two types are connected by intermediate cases to form a whole, so as to indicate that any classification should be artificial.