OF THE GffiBM CELLS <)E METAZOA. 



187 



29. Caiocoris rapidus Say 



Three testes of this species were studied. 



The number of chromatin nucleoli in the rest stage of the spermatogonia was not 

 determined. 



In the most favorable pole view of a spermatogonia monaster were counted about 

 thirty chromatin elements (Plate IV, Fig. 177), but these elements were densely grouped 

 so that I could not be positive as to the exact number. Since there are in the sper- 

 matocytes fourteen bivalent chromosomes, two bivalent chromatin nucleoli and one that is 

 probably univalent, there would be probably in the spermatogonia twenty-eight univalent 

 chromosomes and live univalent chromatin nucleoli, a, total of thirty-three elements. 



In the telophase and rest stages of the spermatocytes there is a, large true nucleolus, 

 which is remarkable in being flattened against the nuclear membrane (A r , Figs. 178, 179); 

 it appears sickle-shaped on cross section, and has irregularly lobular outlines on surface 

 view. In these stages there are live small chromatin nucleoli (N. :.', Fig. 178); one of 

 these is larger than the others and always spherical in form (the larger one of Figs. 178 

 and 179), and since it never appears bipartite is presumably univalent; it is frequently 

 attached to the true nucleolus. The four other chromatin nucleoli are arranged in two 

 pairs, the two components of a pair being connected by a band of linin (Figs. 178, ISO, 

 only one of the pairs shown in Fig. 179). Each one of these four is very small and 

 spherical, and accordingly probably univalent, and each pair would then be bivalent, 

 Thus there would appear to be in the spermatocytes one larger univalent chromatin 

 nucleolus and two bivalent ones, in each of the latter the univalent, components being not 

 closely apposed. 



Pole views of the monaster stage of the first maturation division show always sixteen 

 chromatin elements (Figs. 185, 18G). Three of these are always distinguishable by their 

 much smaller size (N. '2, Figs. L85, 186). These three probably represent the three 

 chromatin nucleoli of the preceding growth period ; two of them appear dumbbell-shaped 

 on lateral view (Fig. 181, and one of the two is shown in Fig. 184), obviously representing 

 the two bivalent ones of the growth period; while the third one always appears rounded 

 and never dumbbell-shaped (Fig. 181, the lowest of the elements designated N. £), and on 

 lateral view of the spindle lies nearer one pole of the spindle than the other (N. $ Fig. 

 183), this one obviously representing the univalent chromatin nucleolus of the growth 

 period. Figs. 181-184 represent oblique lateral views of the spindles, so that in each case 

 only one spindle pole is shown, such oblique views giving the best views ot the chromatin 

 elements. The thirteen remaining larger elements of the first spermatocytes are chromo- 

 somes, and lateral views show (hat twelve of these are dumbbell-shaped and hence prob- 

 ably bivalent; but the thirteenth is quadrivalent, composed of two bivalent (dumbbell- 



