1/8 C. M. CHILD. 



tinuous mass of cytoplasm, which is more or less distinctly 

 marked off from the parenchymal substance, but still shows 

 fibrous extensions into the parenchyma. The development of the 

 testes differs from that of the ovary in that none of the parenchy- 

 mal substance is included within the testis. This difference is 

 merely the consequence of the fact that the testes usually develop 

 from a single nucleus and its surrounding cytoplasm, while the 

 ovary develops from a large number of the parenchymal nuclei. 



II. The Gro-ii'tli of tlic Testes Preceding iJie Spireine Stage. 



During the period preceding the appearance of the spireme in 

 a part of the cells the development of the testes consists of in- 

 crease in size as the result of numerous divisions, chiefly amitotic 

 and of formation of the membrane about the testis and of the 

 vasa efferentia. 



The formation of the membrane occurs at an early stage from 

 the cytoplasm of cells about the periphery of the proliferating 

 mass. Fig. 5, . / (PI. YIII.), shows one of these cells with the 

 membrane forming an extension of the cytoplasm. The vas 

 efferens is formed in the same manner (Fig. 6, A, PI. VIII.). The 

 membrane-forming cells are lew in number and the nuclei appar- 

 ently undergo degeneration in later stages, for they are very rarely 

 fou ml in the fully developed testis. 



The contents differ somewhat in appearance according to the 

 method of fixation employed. After Hermann or chrom-oxalic 

 the nuclei appear in most cases to be imbedded in a syncytial mass 

 of cytoplasm, cell boundaries being indistinguishable or some- 

 times faintly visible, though cavities or vacuoles are frequently 

 observed. After sublimate and some of the sublimate mixtures 

 in all but the earlier stages the cytoplasm appears to have under- 

 gone shrinkage and to be more or less definite!}' concentrated 

 about each of the nuclei. In later stages the individual cells ap- 

 pear more distinct after any fluids. The earliest stages of testis- 

 development are certainly syncytial and without doubt the indi- 

 vidualization of the cells takes place gradually. In consequence 

 of the shrinkage of the delicate and probably highly fluid proto- 

 plasm caused by the sublimate fluids the distinctness of the cells 

 is exaggerated. Most of the figures of these stages (Figs. ;, 



