OP THE GERM CELLS OF METAZOA. 177 



second spermatocyte, one univalent chromatin nucleolus, five uuivalent chromosomes, one 

 semivalent chromosome ; spermatid, one semivalent chromatin nucleolus and either five 

 or six semivalent chromosomes. 



22. Protenor bclfragei Hagl. 



Five testes of this exceedingly interesting species were studied from individuals that 

 had just completed their last ekdysis. 



In the rest stage of the spermatogonia (PI. Ill, Fig. 118) are two rounded chroma- 

 tin nucleoli which are usually attached to the surface of a much larger true nucleolus (N). 



Pole views of the monaster stage of the spermatogonic mitosis show with great dis- 

 tinctness exactly thirteen chromatin elements (Figs. 119-123). This number was found 

 in thirteen cells of one testis, in ahout sixteen cells of a second, in six cells of a third, 

 and in two cells of a fourth these being all the favorable cases found, and all these 

 testes had been fixed with Flemming's fluid (the stronger mixture). The fifth testis 

 sectioned had been fixed in picro-acetic acid, and in it the number of chromosomes could 

 not be counted because of the swelling action which this reagent exerts upon the chroma- 

 tin. These chromosomes are unusually large and on suitable preparations can be counted 

 with exactness. In only two of the cells in which they were counted was there observed a 

 fourteenth element; this was a minute granule (/, Fig. 121), which, on account of its 

 being present so rarely in these monaster stages and on account of there being no 

 element to represent it in the later history of the spermatogenesis, need not be taken into 

 account ; it seems to be very inconstant, and might possibly represent either a portion of 

 chromatin which had become separated from one of the chromosomes, or a chromatin 

 iiucleolus transmitted from some distant parent and now nearly reaching disappearance. 



Which two of the elements in the spermatogonic monaster represent the chromatin 

 nucleoli of the previous rest stage I am unable to determine, but that two of them do 

 represent these bodies there can be no doubt from what has been determined for the suc- 

 ceeding stages; judging by analogy with the case in all other Coreidce examined, they 

 would probably be the two smallest elements. Now Figs. 119-123 show what is to be 

 seen very distinctly in all cases, namely, that there are three chromatin elements much 

 larger than the ten remaining. One of these three, that designated x in Figs. 119-123, 

 imposes by its relatively very large volume ; this has in most cases the form shown in 

 Figs. 120 and 121, but in a few cases it was noticeably elongated, as in Figs. 122 and 

 123. The last figure shows it to have a transverse constriction around the middle ; and 

 this case, together with the fact of its great volume, would show it to be equal potentially 

 to at last two chromosomes ; for purposes of description we shall call this the " chromo- 

 some x." The two other chromosomes, which can always be recognized by their relatively 



