CHROMATOID BODY IN PENTATOMA. 40! 



At every period of its history the chromatoid body is often 

 homogeneous in appearance; but not infrequently it shows more 

 or less definite indications of a central cavity. Here and there 

 one may be found in which the cavity is clearly evident ; and now 

 and then a definite, sharply stained central granule appears within 

 the cavity (Figs. 21, 43). This granule has only been seen in the 

 dividing spermatocytes and in the spermatids. Since centrioles 

 are also seen in these stages they are evidently not derived from 

 the central granule of the chromatoid body. 



Apart from its smaller size, the chromatoid body in the three 

 other species mentioned shows the same general history as in 

 P. senilis. In P. juniperina it is at its maximum size hardly 

 more than half as large as in P. senilis (Figs. 34, 35) ; it is very 

 often accompanied by a much smaller and paler granule lying 

 close beside it (Fig. 35). In Podisus crocatus it is somewhat 

 smaller than in P. juniperina (Fig. 33), in Ccenus delius still 

 smaller and might readily be mistaken for an accidental granule. 

 In all these cases its behavior seems to be of the same type, and 

 it is surrounded by a similar vacuole. In the two forms last 

 mentioned, perhaps because of its small size, its position in the 

 divisions is more variable, and it more often lies away from the 

 spindle or near the periphery of the cell. 



II. 



The nature of the chromatoid body need not here be considered 

 in extenso. As before stated, it is probably of the same nature 

 as the "chromatoid Nebenkorper" described by various observers 

 in other animals; but I know of no case where the facts are in 

 all respects identical with those seen in Pentatoma. In the rat, 

 for example, the "chromatoid Nebenkorper" as described by v. 

 Lenhossek ('98) is in some respect remarkably like that of 

 Pentatoma: but this body (two are often present in the earlier 



1 The elimination of protoplasm from the spermatid is of course a well-known 

 and widespread phenomenon. In the cockroach, as described by Morse ('09) the 

 process appears to be similar to that seen in Pentatoma, and here also a deeply 

 staining body is cast off, which Morse identifies as a plasmasome. I think it 

 possible, however, that this too may be a chromatoid body comparable with that 

 of Pentatoma. I also think it probable that the bodies that have been described 

 as "degenerating cells" in the late spermatid-cysts by some observers are identical 

 with the protoplasmic balls here described. 



