466 
J. BRONTE GATENBY. 
environments. In the Holometabola, we get remarkably 
varying stages of life history, for which assuredly- we would 
look in vain in Murex or Tritonium, and, while admitting 
that in many Prosobranchs the case is so remarkable as to 
permit speculation and theory, I feel that in the Lepidoptera 
we cannot attach any importance to the atypical spermatozoa 
other than that of a degeneration product. 
The special purpose of this paper is an inquiry into these 
degeneration products in moths and butterflies, but the apyrene 
sperm of the mollusc has formed the subject of a note. 
I have to thank Dr. Goodrich for his kind interest and 
criticism. This work was carried out in the Department of 
Physiology, and in this connection my best thanks are due to 
Prof. Sherrington. 
Previous Work. 
Meves (2) alone has given a good account of these atypic 
spermatozoa of moths. But the atypic sperms described by 
him (Pygsera) are not the only kind of apyrene formation of 
moths, and it has been the purpose of this paper to point out 
that it would be a mistake to think that apyrenes arose exclu- 
sively from the time of formation of karyomerites as seems to 
occur in some molluscs (1). 
Quite recently H. Federley 1 (3) has reported upon the 
spermatogenesis of Pygaera anaclioreta, P. civitula, 
and P. pigra, and has been able to describe as much as his 
Carnoy technique would allow. Needless to say this fixative 
has spoilt all cytoplasmic details except the amphiaster, and 
his results from the point of view of this present paper have 
been less successful than those of Meves. Federley has 
given a completely satisfactory account of the apyrene 
maturation divisions in so far as the behaviour of the chromo- 
somes is concerned. This observer also gives an account 
of the chromosomes of the hybrids of the above species of 
Pygaera, which he has worked out well. 
1 For the loan of this paper I am indebted to Dr. J. W. Heslop 
Har rison. 
