DEVELOPMENT OF APYRENE SPERMATOZOA. ^27 



The nurse-cells develop from large cells which are attached 

 to the walls of the testis by a long stalk. These cells closely 

 resemble the apyrene spermatocytes of Strnnifms except that they 

 lack the pronounced centrosome of the latter. The only indica- 

 tion of -uch a structure in the case of L. ncfntlosa is a series of 

 fiber- running up one -ide of the cell. Thi- later di-appcar- 

 ancl probably forms the portion of the cell to which the sper- 

 m.iio/oa are attached Fig. 141. In L. angulifera, in the early 

 stages of the nur-e-cell, tin- re- i- a darkly -taining body lying 

 in the c\topla-m \\hich grow- to form the rod -poken of above; 

 thi- al-o may !> of a run manual origin. The formation of the 

 \olk bod it--, i- much thr -ame as that of thr bodir- dc-rri! n-.l in 

 Strnnilms. Tlu-y diffrr. ho\\r\rr. in that huv the\- reach vi much 

 larger -i/<- and lliui fragment into t\\<> or more parH. Coincident 



\\ itli this cytoplasmic dit'fen-ntiation the nucleus undergoes partial 



.-neration; it -iniph becomes m.T<- and more vacuolated but 



lle\ er ' ' 'IllpleteU d i -a p] lea I'-. 



Before ihe nur-e-cell ha- reached it- full di-\-elopiiu-nt it loses 

 it- connection with the \\all and moves into the lumen of the 

 testis. Mere I lie -permato/oa become attached. The nur-e-cell- 

 IniK lion as -iii-h in the -perm-duct-. Section- ot /.. rmlis, made 

 from a -pecimen killed in Kebruar\ . -ho\\cd the nur-e-cdl- in 

 the -perm-duct- to be in a more or le iU-])lete.l comlitiou. 



LITE 1<A PURE CITED 



Brock. 

 "87 LJebei die :"i>i-lt'''i S|><TIH.U.I/O.-II <-in: luer. 



' J.lllli... H.I. 2. 



Meves, Fr. 



"03 IVI'ri oil] uii'l >M .ii-n uiul iibcr ihr-- Kiit-ti-lnin.;. nach 



iiiiiK'-n an /'ji'://ij uiul I'y^iri.i. Arrhiv I. inikr. An.it. uml 



'.i. 

 Kuschakewitsch, Sergius. 



'n I l-:m\vi. killing '!i-r >i'i-iiiiii-n bei Conns mfJit<rninfns Brug. uml 



\',-r>n,-tns gi'i'(J5 Biv. Biol. Centralblatt, Bd. 31. 



