1902.] NICHOLS— SPERMATOGENESIS 0NISCUSA8ELLUS LINN. 89 



slender extremity of each nucleus for some distance into the clear, 

 homogeneous area (Fig. 77^). At this stage also there can be 

 clearly seen in the undefined mass of cytoplasm a bundle of fibres, 

 which run in between the nuclei, but which cannot be seen to have 

 any connection with them. I have a preparation of a stage, earlier 

 than that just described, stained with hsematoxylin and Bordeaux 

 red, in which these striations appear, near the margin of the follicle 

 (Fig. 73). So early a development of the fibres is rather unusual. 

 The fibres are here apparently incomplete and not massed together 

 as they later are. On account of their indistinctness it is difficult 

 to say whether or not they are independent of the nuclei. At first 

 sight it might appear as if they were continuous, but it is impossi- 

 ble to state definitely that this is so because of the impracticability 

 of tracing a single fibre for any great distance. 



The further changes in the nuclei consist in their gradual elonga- 

 tion into filaments, in which the network has entirely disappeared 

 and which have acquired the power to take a vivid and homogene- 

 ous stain. Their free ends, at first divergent, gradually approach 

 each other and finally come to lie close together (Figs. 77-79, 85 

 and 86). In regions of the follicle where the cells are closely 

 crowded together the nucleus is often seen to be bent or coiled 

 upon itself (Fig. S^). 



There is at first a small quantity of cytoplasm around the nuclei, 

 but as they increase in length this disappears. The cytoplasmic 

 fibres also increase in length at the expense of the surrounding 

 cytoplasm. Their length, indeed, becomes truly marvelous, many 

 times exceeding that of the nuclei. They crowd in between the 

 follicle cells (Fig. 2) and in cross sections of the follicle can be 

 seen in great numbers around the margin. From the anterior end 

 of the bundle is developed a slender flagellum (Figs. 85, 86). The 

 entire bundle has the appearance at first sight of a single sper- 

 matozoon, and such I thought it before having studied its develop- 

 ment. 



The term ''spermatophore " has been applied by Gilson to the 

 bundle. This term, however, has been used by Grobben and others 

 to designate an envelope secreted by the cells of the vas deferens 

 (in the Decapods) and surrounding a mass of spermatozoa. It 

 does not, therefore, seem applicable to the bundle of spermatozoa 

 found in the Oniscidse. Ballowitz applies the term *'spermozeugma" 

 to a large bundle of double spermatozoa found in the vas deferens 



