THE SPERMATOGENESIS OF SCUTIGERA FORCEPS. 



GRACE MEDES. 



INTRODUCTION. 



In the present paper it is my purpose to note briefly some 

 observations upon the spermatogenesis of Scntigera forceps. 

 The spermatogenesis of Cliilopoda has been the subject of a num- 

 ber of investigations during the last few years besides the earlier 

 ones of Carnoy and Prenant. Carnoy, in his pioneer monograph 

 on " Cytodierese Chez les Arthropodes," demonstrated the value 

 of this material by a series of observations on Geopliilits, Lithobins, 

 Scittigera and Scolopendra, although many of his results have 

 been disproved by later investigators. The most suggestive part 

 of this work has to do with the various kinds of nucleoli and 

 their composition and structure. He divided these bodies into 

 four classes : nucleoles mtclciniens, mtclcoles plasmatiqitcs, nnc- 

 Icolcs mixtes and nucleoles noyaux. In Chilopods, he found two 

 of these : nucleoles noyaux in Litlwbius forficatus, Scntigera 

 arachnoides and Geophilus ; and nucleoles plasmatiques in Scolo- 

 >pendra dalmatic a. 



Prenant worked upon Scolopcndra and Litlwbins, his results 

 being very similar to those obtained later by P. and M. Bouin. 

 These two, in connection with R. Collin, have worked upon 

 several forms of Chilopods, Lithobiusforficatus, GeopJiilns linearis 

 and Scolopcndra morsitans. These authors have concerned 

 themselves principally with cytoplasmic structures, although 

 they have given some attention to nuclear structures as well. 

 The large nucleolar bodies found in LitJiobius and Geopliilus, 

 according to them, are of an achromatic nature, and would cor- 

 respond more closely to Carney's nucleole plasmatique. The 

 chromosomes are not derived from this body, but arise from 

 granules scattered through the nucleus. 



The results obtained by Meves and von Korff upon LitJiobius 

 forficatns are, in general, in accordance with those of Bouin. 

 They take the same view in respect to the origin of the chro- 



156 



