ORTHOPTERAN SPERMATOGENESIS 699 



in the studies of different investigators, working upon similar 

 materials secured from widely different sources, and through a 

 great variety of technical methods. As a most marked instance 

 of such concordance of results may be mentioned the accounts 

 of spermatogenesis in Stenobothrus. This genus has been studied 

 very generally and by cytologists of France, England, and America 

 — Carnoy, de Sinety, Girard, Meek, Davis — and yet the pub- 

 lished accounts upon the same species show practical agreement 

 upon the uniformity of number, sizes, forms and behavior of the 

 chromosomes in different generations. If there were not genetic 

 relations of the most exact character such agreements would 

 be impossible. In a similar way, with the exception of the 

 Stenobothrus-like species, and Pamphagus, the students of the 

 Acrididae have reported a reduction of the 23 spermatogonial 

 chromosom.es to 12. Among this haploid number may be recog- 

 nized the unpaired accessory chromosome and 11 paired elements 

 whose members correspond in size, at least, with those of the pre- 

 vious generation. 



Regarding the details of such a relation there is not a com- 

 plete uniformity of opinion, but there is agreement upon the 

 fact that by an association between definite m.embers of the sper- 

 matogonial complex there are produced the bivalent structures 

 of the first spennatocyte. For the Acrididae this is the opinion 

 of Montgomery, Davis, Buchner, Brunelli, Sutton, Pinney, 

 Nowlin, Robertson, Carothers and myself. Although the other 

 families have been less studied these genetic relations appear to 

 exist in the Locustidae according to Davis, Buchner, Stevens, 

 and by both Otte and Vejdovsky despite their views upon the 

 character of the maturation divisions. For the Gryllidae Baum- 

 gartner and Payne; for the Blattidae Farmer and Moore, Stevens, 

 and Wassilieff ; and for the Phasmidae Jordan, are in agreement 

 on the direct relation between the spennatogonial chromosomes 

 and those of the first spermatocyte. 



Of the greatest importance in determining the relations of 

 chromosom.es to each other in successive cell generations is the 

 behavior of the accessory chromosome. There is almost uniform 

 agreement regarding its direct and evident continuity, without 



JOURNAL OF MORPHOLOGY, VOL. 25, NO. 4 



