SPERMATOGENESIS OF PASSALUS CORNUTUS. 415 



highly indicative of an interaction between nucleus and cyto- 

 plasm. The relation of this zone to the mitochondria seems to 

 be a strong argument, at least, that it is the locus of mitochondria 

 formation. 1 



The association of the spindle and the mitochondria has led 

 to some confusion in regard to the origin of the Nebenkern, so 

 that some workers have ascribed its origin to the spindle remains 

 of the second maturation division. Arnold (1908) comes to this 

 conclusion in his study of Hydrophilus, as does Baumgartner in 

 Gryllus. Voivnov, as previously mentioned, derived the Neben- 

 kern from his "zona interna" and the peripheral spindle fibers. 

 Munson (1906) in his work on Papilio also derives the Nebenkern 

 from the spindle remains, but his observations are interesting 

 since they clearly show that he has confused these with the 

 mitochondria. According to his view, it is only the "outer, 

 granular" mantle fibers of the spindle which take part in 

 the formation of the Nebenkern. It is evident, in light of 

 the recent work, that the "outer, granular" mantle fibers are 

 really mitochondria. That he actually saw the mitochondria 

 and misinterpreted them, is evident from the following quotation: 

 "Often a few scattered chromatin segments are found scattered 

 along the spindle fibers, or else drawn out into stainable threads 

 parallel with the spindle fibers" (p. 91). 



(c) Spindle Derivatives. 



When one attempts to review the literature on the subject of 

 spindle derivatives and their histories, one is immediately con- 

 fronted with a maze of conflicting observations and interpreta- 

 tions, to say nothing of a nomenclature which is almost hope- 

 lessly confused. The names mitosome, idiozome, attraction- 

 sphere, centrosphere, astrosphere, Nebenkern (of older workers), 

 etc., are all examples of the existing confusion, and should caution 

 us against hasty interpretations of such structures. Meves 

 (1899) states that he first applied the term "idiozome" to those 

 compact bodies in the spermatogonia and spermatocytes which 



1 It is interesting to note in this connection that the material of the yellow 

 crescent in the ascidian egg has been shown by Conklin to be found at various 

 times in a perinuclear position; and Duesberg (1913) has shown that this zone 

 is extremely rich in mitochondria. 



