DEGENERATE (APYRENE) SPERM-FORMATION OF MOTHS. 487 
EXPLANATION OF PLATE 26, 
Illustrating Mr. J. Bronte Gatenby^s paper, “ The Degenerate 
(Apyrene) Sperm-formation of Moths as an Index to 
the Inter-relationship of the Various Bodies of the 
Spermatozoon.” 
Explanation of Lettering. 
A. Acroblast or acrosome. C. Centrosome C.O. Chromophobe 
vacuole of mitochondria. C.H. Chromosomes. F. Axial filaments. 
F. IP. Follicle wall. G. Granule. M. Mitochondria (macromitosome). 
M.I. Micromitosome. N. Nucleus. W.X. Nucleus being formed from 
single chromosomes. X.Y.Z. Different regions in the macromitosome. 
[All figures drawn from an 18-compensating eyepiece and a Koritska 
Agth semi-apochromatic oil immersion, with a camera lucida, at table 
level. In reproduction figures reduced by one half. Now x circa 
2000 diameters.] 
PLATE 26. 
Fig. 1. — Four spermatids of Smerinthus populi showing ab- 
normal multinucleate condition resulting from a failure of the chromo- 
somes to fuse up normally after second maturation division. The 
mitochondria in the top left-hand cell are less abnormal than those of 
the other cells. 
Fig. 2. — Spermatid of S. populi showing all cell elements normal 
except the nucleus, which has not been reconstructed from the chromo- 
somes. The latter, singly or in small numbers, are forming a group 
of separate nuclei. 
Fig. 3. — Young spermatozoon of Pieris, quite normal except that the 
nucleus is falling away. At X. is the front end of the macromitosomal 
spireme (January). 
Fig. 4. — Second maturation division of S. populi, showing a lagging 
in the chromosomes. The mitochondria are normal. 
Fig. 5. — Advanced spermatozoon of Pieris brassicse, showing 
abnormal elongation of macromitosome. 
Fig. 6. — Spermatid of Smerinthus populi with five nuclei; other- 
wise quite normal. 
Figs. 7, 8, 10, and 11 show in P. brassicse the falling away of the 
nucleus in the elongating spermatids. Latter otherwise normal 
(January). 
