SPERMATOGENESIS OF THE MYRIOPODS. 



\'I. AN ANALYSIS OF THE CHROMOSOME GROUP OF 



Scolopenda heros. 1 



M. \V. HI.. \CKMAN. 



I hiring the last few years a number of attempts have been made 

 to analyze the chromosome complex of various animals. These 

 attempts have met with such apparent success in the case of 

 several insects, notably Orthoptera, that I have been led to 

 attempt a similar analysis of the chromosome group in Scolopendra 

 heros. Indeed, before the appearance of earlier papers upon this 

 species such an attempt had been made, but it had met with but 

 small success owing, as I now know, to deficiencies in the optical 

 apparatus employed. With the facilities then at my disposal, it 

 was impossible to secure definite clear-cut images of the chromo- 

 somes at a magnification greater than 1,500 diameters. As the 

 chromosomes in Scolopendra heros, although exceedingly clear- 

 cut and definite in outline, are considerably smaller than in some 

 insects, a greater magnification- than 1,500 diameters is necessary 

 if the study is to be at all convincing, either to the investigator or 

 to those reading his report. However, by the use of a Zeiss 2- 

 mm. apochromatic objective and a number 12 compensating 

 ocular, the source of light being a Welsbach mantle, a magnifica- 

 tion of 2,300 diameters was obtained with no perceptible loss of 

 definition in the image. 



The material used in this study is the same which served as a 

 basis of several previous papers 2 (Blackmail :oi, 103, 105), the 



'From the Zoological Laboratory, Syracuse University, Syracuse, New York. 



'Blackman, M. W., :oi, "The Spermatogenesis of the Myriapods I., Notes on 

 the Spermatocytes and Spermatids of Scolopendra," Kans. Univ. Quart.. Vol. 10, 

 pp. 61-76, pi. 5-7. 



Blackman, M. W., 103, "The Spermatogenesis of the Myriapods II., On the 

 Chromatin in the Spermatocytes of Scolopendra heros," BIOL. BULL., Vol. 5, pp. 

 187-217, 22 fig. 



Blackman, M. \V., 105, "The Spermatogenesis of the Myriapods III., The 

 Spermatogenesis of Scolopendra heros," Bull. Mia. Comp. Zoo/., Harvard ('<//. 

 Vol. 48, No. i., pp. 1-137, 9 pl- 



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