Journal of experimental zoology . 7 Frequency 1 2 3 2 2 2 6 7 12 21 21 24 25 34 29 44 53 62 57 59 96,5 73 51 38 26 41 17 19 7 7 2 9. Gryllus abhreviatus (a) Spermatogenesis evidence concerning dimorphism. Thechromosomal relations for this species are not known. Anotherspecies of the same genus, G. domesticus, has an X chromosome,according to W. J. Baumgartner (05). (6) Material and method. Obtained at Douglas Lake, Michi-gan, August 23, 1913; motile in Ringers solution; killed in
Journal of experimental zoology . 7 Frequency 1 2 3 2 2 2 6 7 12 21 21 24 25 34 29 44 53 62 57 59 96,5 73 51 38 26 41 17 19 7 7 2 9. Gryllus abhreviatus (a) Spermatogenesis evidence concerning dimorphism. Thechromosomal relations for this species are not known. Anotherspecies of the same genus, G. domesticus, has an X chromosome,according to W. J. Baumgartner (05). (6) Material and method. Obtained at Douglas Lake, Michi-gan, August 23, 1913; motile in Ringers solution; killed inosmic fumes; diagram of sperm-head in figure 10 c; measure- 226 CHARLES ZELENY AND E. C. FAUST ments were to halves of ocular divisions, one division being equalto (c) Data. Figure 35; 552 spermatozoa from the right testis. (d) Conclusion. The curve is unimodal. It is not possibleto teU by inspection whether it is a simple normal variationcurve (fig. 1) or a combination of two such curves with modesclose together (fig. 6).. Fig. 35 Gryllus abbreviatus; frequency distribution of head-lengths of 552spermatozoa from the right testis. Value in M Frequency 2 1 5 5 7 19 20 22 39 49 57 57 58 49 45 30 13 10 4 2 3 10. Aeshna canadensis (a) Spermatogenesis evidence concerning dimorphism. Thechromosomal relations are not known for this species, but inanother dragon fly, Anax Junius, Lefevre and iMcGill (08)have described an X chromosome. The following measure-ments are taken from their figure 4 e. SIZE DIMORPHISM IN SPERMATOZOA 227 Chromosomes Width Length Chromosomes Width Lengt a 18 23 h 27 33 b 20 30 i 21 28 c 21 27 J 20 27 d 14 16 k 19 28 e 20 27 1 20 26 f 18 25 m 24 34 g 16 21 X 23 31 These give expected ratios of : on the basis of com-plete fusion of chromosomes and production of spermatozoa oflike shape and : for end to end fusion of chrom
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