226 NEIL S. DUNGAY. 



(/) When the larval setae should form, it often happens that 

 none or only a few of them appear. In some cases this was 

 true of more than half of the larvae. Very few experimental 

 cultures showed less than 5 per cent, of such forms. There may 

 be all grades of conditions from no setae, through a few scattering 

 ones, weak ones, and abnormally directed ones, to nearly perfect 

 forms. In cultures inseminated with normal sperm, very adverse 

 external conditions may produce this effect or something, in a 

 small number of the larvae, very much like it. But under the 

 very best conditions that could be maintained this was always 

 found in the experimental material, though never in the controls. 

 Associated with this condition was the partial or complete lack 

 of sensory appendages. 



(m) The body form is sometimes altered. It may be perma- 

 nently bent toward one side by the asymmetrical development of 

 a single segment. Often the body is covered with small wart like 

 projections, giving it a peculiar roughened appearance. 



(n) The experimental cultures nearly always show a lack of 

 vitality, as is evidenced by a lessened activity. The normal 

 cultures are very active after reaching the motile stages. The 

 others, at least in part, are usually more or less quiescent. The 

 phototropic responses are much less uniform in the experimental 

 cultures and do not take place so quickly. 



(0) In addition to the above list of abnormalities there is 

 always present, unless the unfertile eggs are removed from the 

 cultures, a number of other types which are confusing at first. 

 As it is not always possible to remove every unfertilized egg 

 during the first few hours, one is likely to find a variety of things 

 which are easily misinterpreted unless they are very carefully 

 studied. Unless such things have crept into my counts through 

 an occasional oversight no consideration will be given them. 



Nearly all of the above list of abnormalities were present in 

 most of the experimental cultures if they were not discontinued 

 too early. The controls rarely produced any of them. The 

 proportions of the different types naturally differed widely in 

 the various experiments. If the sperm cells were injured to the 

 limit, or nearly so, the abnormalities were largely confined to the 

 early stages and death occurred before the later ones could ap- 



