FOUND IN THE COELOM OF SAG ITT A. 



321 



Fi g- 4- 

 X960. 



A very young in- 

 dividual in longitudinal 

 seetion. y.g(c. 



The body is covered with short cilia, which, instead of being arranged in 

 longitudinal bands, are uniformly distributed all over. The cytoplasm 

 presents much the same appearance as in the full-grown state. Situated in 

 one part of the entoplasm is distinctly recognizable 

 - . the micronucleus, which is of nearly the same shape 



and size as before described. What now form the 

 Striking features of the sta^e under consideration 

 are the state of the meganucleus and the entire 

 absence of a large central non-plasmic body. 

 The meganucleus is not only very much smaller, 

 but is also of a much simpler configuration, than 

 in the fully developed state. In fact, it now con- 

 sists of a relatively thick and sinuously winding 

 thread, which may bear some short branches ending 

 free. Some small empty-looking spaces, which I 

 take for the excretory vacuoles, occur either close 

 to or in direct apposition to the meganucleus. Further 

 there occur in the entoplosm and in the vicinity of 

 the nuclei, some small spherical, but sometimes 

 somewhat irregular-shaped, bodies which agree in 

 appearance and staining reactions perfectly with the 

 substance forming the single central non-plasmic body of full-grown in- 

 dividuals. They may be designated the non-plasmic spherules for the sake 

 of reference. I shall return to them presently again. 



In still larger young individuals than those described above, all the 

 structures referred to can be more distinctly made out. The individual 

 shown in two longitudinal sections in fig. 6 measures about 40// by 20^. In 

 it, as observed on the sections, the densely granular ectopiasm can be well 

 distinguished from the reticular entoplasm, though the two gradually merge 

 into each other. The micronucleus is found in the usual state and can be 

 readily recognized. The meganucleus has approached a step towards the 

 basketwork-like structure of that of full-grown individuals, that is, it now 



Two couse cutive 

 cuoss-s-etions through 

 a very young indinid- 

 ung. XgEo. 



