PLATE 4 



EXPLANATION OF FIGURES 



36 Anterior end of axial bundle protrudes from spermatosome. Free fla- 

 gella at posterior end have increased in length. 



37 Further growth of axial bundle. As fibres elongate and project farther 

 out of anterior end, they carry part of the cytoplasm of the cell body along with 

 them. 



38 Anterior ends of hbrcs remain close together in a dense bundle, while 

 farther posteriorly considerable cytoplasm is deposited between them. Core 

 becomes prominent in centre of axial bundle (c). Before the spermatosome has 

 reached this stage it has already begun to show rapid movements. 



39, a and h Adult apyrene spermatozoon, drawn in two sections to preserve 

 same magnification as former figures. 39a, anterior; 396, posterior. Cyto- 

 plasm of cell now entirely applied to axial bundle and flagella. An entire apy- 

 rene spermatozoon, on smaller scale, shown in figure 61, together with eupyrene 

 spermatozoon for comparison. 



39c Cross section through middle or posterior part of the adult apyrene 

 spermatozoon. Axial fibres arranged around the periphery of the cytoplasm; 

 in the centre, darkly staining core. 



40a Optical cross section through body of spermatosome at about the stage 

 of figure 37. Axial bundle flat in cross section. 



406 Optical cross section through cell body of a spermatosome at about 

 the stage of figure 38. Axial fibres no longer form a flat bundle, but are dis- 

 tributed about central core. 



60 



