THE SPERMATOGENESIS OF ACiALENA N.EVIA. 151 



the presence or absence of these peculiar elements, it seems prob- 

 able that an egg fertilized by a spermatozoon possessing the 

 accessory chromosomes develops into a male while an egg fertil- 

 ized by a spermatozoon which lacks the accessory chromosomes 

 develops into a female. The results of my work upon the spider, 

 therefore, furnish further evidence in support of McClung's theory 

 of sex-determination. 



7. Degenerating cells or cell fragments which envelop the 

 ripe spermatozoa in the sperm-ducts come from at least four dif- 

 ferent sources. These are as follows : (rt) Broken down walls of 

 empty cysts, (&) cell bodies from which the ripe spermatozoa have 

 escaped, (V) "connecting bodies" of sister spermatids, and their 

 contained mid-bodies, (d] large, oval cells which resemble the 

 rolled up spermatozoa, in size and outline. 

 UNIVERSITY OF PENNSYLVANIA, 

 May, 1908. 



LITERATURE. 

 Balbiani, E. G. 



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Arachmides. Arch. Anat. mic. , V. I., fasc. I. 

 Van Beneden, E. 



'83 Maturation de I'lEif, la Fee m Nation et la Division Cellulaire. Arch, de 



Biol., IV. 

 Berry, E. H. 



'06 The "Accessory Chromosome" in Epeira. Biol. Bull., XI., No. 4. 

 Bertkau, Ph. 



'77 Ueber die Uebertragungsorgane und die Spermatozoen der Spinnen. Verk. 



nat. Ver preuss. Rheinlande. Westfalen. 

 Birula, A. 



'94 Untersuchungen uber den Bau der Geschlectsorgane bei den Galeodiden. 



Horac Soc. entomol. Ross, XXVIII. 

 Blackman, M. W. 



'01 Spermatogenesis of Myriapods, I. Notes on Spermatocytes and Spermatids 



of Scolopendra. Kans. Un. Quart., X. 

 '03 Spermatogenesis of Myriapods, II. On the Chromatin in the Spermatocytes 



of Scolopendra heros. Biol. Bull., V. 

 '05 Spermatogenesis of Myriapods, III. Spermatogenesis of Scolopendra heros. 



Bull. Mus. Comp. Zool. Harvard, XLVIII. 

 Boring, A. M. 



'07 A Study of the Spermatogenesis of Twenty-two species of the Membracidze, 

 Jassidse, Cercopidce and Fulgoridre, with Especial Reference to the Behavior 

 of the Odd Chromosome. Jour. Exp. Zool., IV. 

 Bosenberg, H. 



'04 Zur Spermatogenesis bei den Arachnoiden. Zool. Anz., XXVIII., No. 3. 

 '05 Beitrage zur Kenntnis der Spermatogenese bei den Arachnoiden. Zool. 

 Jahrbuch, XXI. 



