Hermaphroditism among the Apodidae. 297 



the "sperm- forming centres"; liad the latter been found, the 

 results would doubtless have ere now been published. In the 

 meantime I have been continually hoping that someone, more 

 fortunate in obtaining material, would publish a full account, 

 giving the details which were not to be found in my own 

 slides. I did not myself feel justified in publishing a detailed 

 account based upon indifferently preserved material. 



1 have now, however, waited four years, and not only has 

 no one rediscovered the hermaphrodite condition of Apus, 

 but those who have actually looked for it have not succeeded 

 in finding any traces of it. After all, then, it appears that 

 my experience must have been a marvellous one. Three 

 specimens belonging to separate species collected in diffe- 

 rent regions are examined in rapid succession, in order to 

 look for a condition already ascertained to be normal in 

 another member of the same family, and in each case the 

 same condition is found, and since then it has never been 

 found again ! Under these circumstances I feel that any 

 further hesitation to make the best of my slides and to give 

 the results of my observations for what they are worth would 

 be inadvisable. The bare facts, however lacking in finer 

 detail, are evidently worth recording. After reading Dr. Ben- 

 ham's paper, therefore, I resolved to examine my slides, some 

 of which had never been looked at again since they were 

 prepared, and record all that the best microscopic objectives 

 could show in them. 



Before giving these results I may mention two circum- 

 stances connected with the case which will help further to 

 justify my delay, if any more justification is needed. 



While I found in Germany no hesitation in pronouncing 



the minute cells to be sperm-cells, in England there has been 



much diflerence of opinion. This naturally made it all the 



more incumbent on me to wait until I had material which 



showed the process of formation of the cells in question. In 



this 1 was further confirmed when, some three years ago, I 



asked my friend Mr. J. E. S. Moore, at that time working in 



the Huxley Research Laboratory of the Eoyal College of 



►Science, if he would take over the whole subject and work it 



out. 1 handed him the slides and all my remaining material, 



including the Branchijms. Unfortunately the slides which I 



most wished him to investigate, not showing the finer processes 



of cell-division which at that time monopolized his thoughts, 



received but scant attention. In his paper " On the Origin of 



the Reproductive Elements in Ajms and Branchipus " * he 



* Quart. Journ. Micr. Sci. vol. xxxv. 1894, p. 277. 



