STUDIES ON INSECT SPERMATOGENESIS

I. THE HISTORY OF THE CYTOPLASMIC COMPONENTS OF THE SPERM IN HEMIPTERA

¹ From the Department of Zoölogy, Columbia University

1. In Euschistus the mitochondrial material of the primary spermatocytes occurs in the form of threads which are definitely oriented toward the centrioles in the prophases of the maturation divisions.

2. Due to this very definite arrangement, the threads are so distributed during the anaphases that each daughter cell contains one half of the mitochondrial material.

3. The mitochondria are not divided autonomously on the spindle but as a result of their position or the mechanical action of the constricting cell wall.

4. The Golgi apparatus of the spermatocytes is extensively developed, occurring in the form of scattered Golgi bodies.

5. During the maturation divisions these bodies undergo a process of autonomous fragmentation into dictyosomes which are arranged in a definite relation to the spindle and are then distributed in equal groups to the daughter cells. The arrangement and distribution of the Golgi elements during division is clearly dependent upon the centrioles.

6. In the spermatids the Golgi elements are condensed into a single body, the acroblast, from which the acrosome of the mature sperm is derived.

7. The remnant of the acroblast (or Golgi remnant) ultimately breaks free from the acrosome and is lost in the cytoplasm of the tail probably taking no further part in the formation of the sperm.

8. The centrioles of the spermatid are, as in most (all?) animals, paired, and in this case remain in the "neck" region of the mature sperm.

On the basis of the facts brought out in this study it is suggested that:

1. The regularity in the division of the cytoplasmic elements of the cell, as illustrated by the mitochondria and Golgi bodies of Euschistus, is not the result of chance but is accomplished by a definite mechanism focused in the centrioles, and may perhaps partake of the nature of a meristic, as contrasted to a mass division.

2. The acrosome of the animal sperm is probably universally formed in connection with the Golgi apparatus, and has nothing whatever to do with spindle fibers or other cell parts. It is to be considered as much a characteristic part of the sperm, having a definite morphological value, as are the nucleus and mitochondria.

3. The idiosome plus the Golgi apparatus of vertebrates and pulmonates is to be considered as the homologue of the scattered Golgi bodies of insects, the idiosomic substance and the Golgi material being in some way intimately related, possibly in the sense of an essentially single cell organ of duplex chemical nature.