36 
Fics. 
Fics. 
FIGs. 
Fics. 
Papers from the Marine Biological Laboratory at Tortugas. 
122) 
125, 
128, 
192; 
123, 124. Three spermatids, showing the various shapes and locations of 
the accessory chromosome. 
126, 127. Successive stages in the metamorphosis of the spermatid to form 
the spermatozoon; the accessory chromosome shown in form of a central 
intensely chromatic sphere. These same cells show a polar cap of chro- 
matic material (this seen only in iron-hematoxylin preparations). The 
second contains a mass of eliminated chromatin in its cytoplasm and 
karyosomes in the nucleus. A short, slender chromatic filament has grown 
out from the centrosome into the cytoplasm. 
129, 130, 131. Successive stages in the later development of the sperma- 
tozoon. Only one-half contain a chromatin nucleolus (accessory chromo- 
some). The cytoplasm has elongated into a tail through which extends 
the slender chromatic filament much enlarged at the nucleo-proximal 
end to form a middle-piece or neck. 
133, 134, 135. Successive stages in the final development of the sperma- 
tozoon, showing the progressive disintegration of the chromatin nucleolus 
(accessory chromosome—still U-shaped in figure 133). 
Fic. 136. Mature spermatozoon stained in iron hematoxylin; showing chromatic archo- 
plasmic cap, vesicular head (nucleus), chromatic neck, and axial filament 
with spiral cytoplasmic fin. 
Fic. 137. Mature spermatozoon stained in methyl green (thionin yields similar result) 
showing an achromatic archoplasmic cap, a chromatic head, and an achro- 
matic cigar-shaped neck. 
Fics. 138, 139. Two of the final stages in the formation of-a giant spermatozoon. 
