Thesis presented to the Faculty of the Graduate School of the University of 
Pennsylvania in partial fulfillment of the requirements for the degree of Doctor 
of Philosophy. 
THE SPERMATOGENESIS OF ASCARIS MEGALOCE- 
PHALA WITH SPECIAL REFERENCE TO THE TWO 
CYTOPLASMIC INCLUSIONS, THE REFRACTIVE 
BODY AND THE ‘MITOCHONDRIA’: THEIR ORIGIN, 
NATURE AND ROLE IN FERTILIZATION 
EDWARD E. WILDMAN 
Zoological Laboratory of the University of Pennsylvania 
FORTY-EIGHT FIGURES 
In 1906 Marcus made two notable contributions to our knowl- 
edge of nematode spermatogenesis. ‘The first was his discovery 
‘that the refractive body is formed within the vas deferens in 
Ascaris canis, thus completing the spermatogenesis within’ the 
male. Previously this most unique and characteristic structure 
of the nematode spermatozoon had been seen only in those cells 
which had already entered the uterus of the female. This dis- 
covery was confirmed by Mayer (’08) and Romieu (’11), both 
working with A. megalocephala. 
Marcus also suggested that the ‘protoplasmic corpuscles’ or 
‘microsomes,’ observed by Van Beneden, Hertwig and others 
surrounding the chromatic mass in the spermatid, were mito- 
chondria. This interpretation has been supported by Mayer (’08), 
Romieu (’11), Meves (’11) and Faure-Fremiet (’11), all working 
with A. megalocephala.t 
But none of these workers made any attempt to learn the 
origin or to trace the development of either the refractive body or 
the mitochondria up to their appearance in the complete sper- 
matozoon. It seemed very desirable to do this, now that we know 
that the entire development of the paternal germ cell takes place 
1 Since this paper was written, Romeis has published a study of the degenera-, 
tion of the ‘condriosomes’ in Ascaris spermatozoa, in which he also calls these 
bodies mitochondria. 
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