86 H. E. Jordan, The Spermatogenesis of the Opossum etc. 
The chondriosomes (mitocliondria) are seen to group themselves about the filament 
in the region of the future middle-piece. 
Fig. 81. Still later stage sliowing the fomiation of the spiral filament of the 
middle-piece from chondriosomes. A special Nebenkem-remnant is here still visible 
in the anterior open portion of the head. 
Fig. 82. Stage showing the spiral filament of the middle-piece complete ; shows 
also the open V-shaped area in the upper ventral portion of the body, and possibly 
the degenerating idiozome. A centrosome apparently persists as the end-knob of the 
cigar-shaped middle-piece. 
Figs. 83, 84, 85 and 86. Four illustrations of spermatozoa at late stages of 
development, The first and third show the persisting Nebenkem-remnant and the 
second and fourth probably the disintegrating idiozome. 
