144 Dr. O. Zacharias on the Reproduction and 



the interior of the chitinons cuticle. Seen from the surface 

 they appeared somewhat differently. I now ascertained that 

 the cuticle immediately over the egg was perforated, and that 

 the micropyliform opening thus produced appeared to be sur- 

 rounded by a small annular wall (fig. 5) *. 



I have seen such " eerers " attached from within both at the 

 anterior and posterior ends of the body in my Rotifers. 

 That any definite position was preferred for their attachment 

 could not be perceived. Nevertheless it sometimes seemed as 

 if the anterior part of the body-cavity (on the right) and the 

 posterior part (on the left) more frequently bore " eggs " 

 attached to them than other places. The appearance of the 

 structures in question, when they have attained their defini- 

 tive size, is shown by fig. 6. The whole forms an oval 

 hyaline vesicle, at one pole of which there is a globular finely 

 granular structure ; while in the neighbourhood of the micro- 

 pyloid aperture a vacuole-like cavity has been developed. 

 I think I have observed that the vacuole can change its 

 place within the vesicle ; in many cases I have seen it in the 

 immediate neighbourhood of the globular structure. The 

 latter appeared to me to be capable of certain amoeboid move- 

 ments ; 1 have seen it sometimes furnished with knobs and 

 blunt diverticula, which, however, were retracted after a short 

 time. 



Up to this point I had made my observations under a 

 power of only 550 diameters, but now it occurred to me to 

 examine the vacuole, which, under this power, appeared quite 

 light and clear, with a Leitz oil-immersion objective (of j$- 

 inch focus and a numerical aperture of 1*25). The employ- 

 ment of this objective gave a power of 900 diameters. 



When I now glanced into the microscope my astonishment 

 was great. The vacuole showed in its interior numerous 

 swarming filaments, and, indeed, most of them were accumu- 

 lated at the side where the wall of the vacuole touched the 

 globular body (fig. 7). What were these filaments? 



►Since I became acquainted with Ganin's previous obser- 

 vation I had no other thought, a priori, but that I had before 

 me true (although differently formed) eggs of Rotifer, and in 



* On a careful examination of tig". 1 (Stephanoceros Eirlihornii) on the 

 first of the four plates which Prof. Leydig has appended to his tine 

 memoir on the structure and systematic position of the Rotatoria, I see a 

 structure, marked with the letter h (on the right at the fore part of the 

 animal), of which the distinguished histologist confesses that its significance 

 was unknown to him. He describes it as " a group of limpid vesicles 

 which open on the cuticle by a duct, which, although short, is distinct 

 in a suitable position." Have we not here a similar observation to that 

 which I have frequently made in Rotifer P 



