Studies on Chromosomes JI 



"accessory" chromosome) the others being regarded as in a certain 

 sense comparable to polar bodies (as was also supposed by Wallace 

 ('05). 3 This result was based mainly on the numerical relations, 

 and especially on the belief that in both these forms the number of 

 chromosomes is an even one and the same in both sexes twenty- 

 two in Syromastes, twenty-four in Pyrrochoris. Since the com- 

 plete reduced number (eleven and twelve in the two respective 

 cases) is present only in those spermatozoa that contain the 

 "accessory" chromosome, Gross argues that this class alone can 

 be concerned in fertilization, as follows : 



Syromastes Egg n + spermatozoon n = 22(6" or 9) 



Pyrrochoris ...Egg 12 + spermatozoon 12 = 24(d 1 or 9) 



whereas in Anasa or Protenor the relations are: 



Anasa Egg u + spermatozoon 10 = 21 (c?) 



Egg ii + spermatozoon n = 22 ( 9) 

 Protenor Egg 7 + spermatozoon 6 = 13 (c?) 



Egg 7 + spermatozoon 7 = 14(9) 



In the hope of clearing up this perplexing contradiction I 

 endeavored to procure material for a reexamination of the two 

 forms in question, and through the great kindness of Professor 

 Boveri, to whom my best thanks are due, was fortunate enough to 

 obtain an abundant supply of both, though unluckily it includes 

 no female material. 4 As far as the relations can be worked out on 

 the male alone they give, I believe, the solution of the puzzle and 

 bring the two species in question into line with the general princi- 

 ple that has been established for other forms. This is evidently 

 true of Pyrrochoris. i Syromastes, however, constitutes a new 



3 At first thought this seems to be in harmony with the remarkable discovery of Meves ('03, '07) that 

 in the male honey bee actual polar bodies are formed which produce abortive spermatids. Butobviously 

 the two cases are not parallel, for in the bee the fertilized eggs produce only females; and this finds a 

 natural explanation, in accordance with the general conclusions of McClung, Stevens and myself, in the 

 assumption that it is the male producing class that degenerate as polar bodies. 



4 The material, fixed in Flemming's fluid and in Bouin's picro-acetic-formol mixture, is of excellent 

 quality and gave preparations of perfect clearness. The Flemming material is on the whole the best. 

 For single stains Zwaardemaker's safranin and iron haematoxylin were employed (the latter especially 

 for photographs). Various double stains were also used. One of the best, which I can strongly recom- 

 mend to other workers in this field, is the combination of safranin and lichtgriin, which gives prepara- 

 tions of admirable clearness and is also easy to use and certain in its results. 



