EEPRODTJOTIVE ELEMENTS IN APUS AND BRANOHIPUS. 265 



clear globules, kept apart by some non-miseible intervening 

 fluid ;^ in fact, the whole might fitly be described as a foam 

 structure, or " Schaumplasm" of Biitschli. 



I have attempted to give some idea of this appearance in 

 fig. 1, a resting spermatocyte just previous to its division, but 

 the result is not nearly so impressive as I could wish. 



Nuclear stains affect to a certain extent the intervening fluid 

 throughout the whole cell, and the stain appears to be related 

 to excessively fine granules suspended in a clear plasma. 

 These cyto-microsomes do not appear to be " varicosities " of 

 the kytoplasmic strands between the globules, but the stain 

 appears to affect microsomes suspended in this intervening 

 fluid. The whole darkened nuclear area suggests a condensa- 

 tion of this staining material, possibly by its own cohesion. 



Outside the nucleus there are usually to be found, on the 

 side where there is most cell body, and where vom Rath repre- 

 sents the centrosomes in the resting spermatocytes of Gryllo- 

 talpa, those dark points, whose appearance corresponds in 

 everything but number with the centrosomes as ordinarily un- 

 derstood, and which I collected in the more general descrip- 

 tion under the term pseudosomes (figs. 1 — 6, a) . No archoplasm 

 is apparent round them, and a close examination suggests that 

 they are simply the expression of a collection of the above 

 staining material (microsomes) in the angular spaces between 

 the spheroids, producing the reticulate appearance (figs. 1 — 9). 



Careful search will, as I have said, often raise the number 

 of these bodies as high as six or eight. The more we look 

 the more difficult it becomes to separate the pseudosomes 

 from the less conspicuous interspaces of fluid between the 

 globules ; both appear to pass insensibly into each other. 

 The appearance and relation of the more conspicuous are 

 very striking, as observation of their subsequent behaviour 

 left no doubt on my mind that they were intimately bound 

 up, if not with the origin, at any rate with a remarkable 

 increase witnessed in the centrosomes ultimately occupying 



1 When sufficiently high powers are used the appearance is almost identical 

 with the coarse vacuolation in the ectosarc of Amoeba and other protozoa. 



