308 On Hermaphroditism among the Apodidse. 



I do not assert that this is the case. Much more evidence, 

 if possible based upon direct experiment, is needed before such 

 a transformation could be admittedly established. Appear- 

 ances, however, point so decidedly that way that I feel 

 justified in hazarding the suggestion. 



I may, perhaps, add that, startling as is even the suggestion 

 of such a transformation, there is in this particular case 

 hardly any serious morphological difficulty to be overcome — 

 so far as I know, none more serious than the reversion of a 

 single pair of modified limbs to the normal type. In view of 

 the marvellous transformations which occur in other members 

 of the Arthropod phylum at times of ecdysis, such a reversion 

 can hardly be claimed as a difficulty. It seems to me that 

 the most serious objection lies in the extreme improbability 

 of an egg-producing gland changing completely into a sperm- 

 producing gland. If the possibility of such a change is 

 granted, other difficulties appear trifles in comparison. But it 

 is just this change which appears to be so clearly indicated by 

 my slides. 



A propos of the fact that these transformations take place in 

 the parthenogenetic females, it will be remembered that Pel- 

 seneer, in a valuable paper on u Hermaphroditism in 

 Mollusca," endeavoured to show that here also this condition 

 has been superimposed upon the female *. He suggests the 

 following stages : — production of spermatozoa in parts of the 

 ovaries ; reduction in size and number of the males ; complete 

 replacement of females by hermaphrodites ; final disappear- 

 ance of the degraded males. Viewing the Apodidaj in the 

 same manner, we may suggest the following account of the 

 reproductive arrangements of the family: — Parthenogenetic 

 reproduction with suppression of males was brought about by 

 the superabundance of food in the early summer, i. e. during 

 the season of growth and most rapid multiplication. When 

 the pools dry up and food becomes scarce it is necessary to 

 produce resting eggs, for which fertilization is necessary. 



* Quart. Journ. Micr. Sci. vol. xxxvii. 1895. Pelseneer, following 

 Brock (Zeitschr. wiss. Zool. xliv. 1886), claims that the same is also true 

 of the fishes. The recent announcement by Schneider (Mem. Acad. Imp. 

 Sci. St. P^tersb. (8) t. ii. no. 2) that in Cobitis and Phoxinus the genital 

 ducts of the opposite sexes are homologous with each other and with the 

 Miillerian duct appears to support this. Pelseneer, however, makes no 

 mention of the recent papers by Howes (Journ. Linn. Soc, Zool. 

 vol. xxiii. p. 539) and Stewart {ibid. vol. xxiv. pp. 69, 70), nor of others 

 dealing with the subject, therein cited ; this is the more unfortunate, as 

 Stewart's description of a hermaphrodite trout with fully developed 

 genital ducts and " fundamentally a male," tells directly against Brock's 

 hypothesis. 



