214 THE MICROSCOPIST. 



only permits us to glance at the essential structures, 

 which are the seminiferous tubules for the secretion of 

 spermatozoa, in the male, and the ovary for the production 

 of the germ, or ovum, in the female. 



The tubuli seminiferi are a multitude of fine and tortuous 

 tubules contained in the testis, with its accessory epididy- 

 mis. They lie in the interstices of sustentacular connec- 

 tive tissue, and consist of membranous tubes filled with 

 cells, which are said to possess amoeboid motion. During 

 the virile period these glandular tubes generate the sper- 

 matozoa, or microscopic seminal filaments. The shape of 

 these spermatozoa is filiform in all animals, but vary in 

 different species. In man they consist of an anterior oval 

 portion, or head, and a posterior flexible filament, or tail. 

 Different observers have taken different views as to the 

 origin of these structures. Some suppose them the product 

 of special cells, others trace them to the nuclei of the 

 glandular epithelium, while others regard them as ciliated 

 elements formed by the metamorphosis of entire cells. 

 Their motions baffle all attempts at explanation, although 

 quite similar to those of ciliated epithelium. The sperma- 

 tozoa penetrate by their movements into the interior of 

 the ovum, in order to impregnate it, and in the mammalia 

 in considerable numbers. 



The ovary may be divided into two portions : a medul- 

 lary substance, which is a non-glandular and very vascular 

 connective tissue, and a glandular parenchyma enveloping 

 the latter. The surface of the ovary uncovered by peri- 

 toneum is coated with a layer of low columnar cells, called 

 the germinal epithelium. Immediately under this is a 

 stratum called the zone of the primordial follicles, or cor- 

 tical zone. Here the young ova lie crowded in layers. 

 They consist of granular bioplasm, containing fatty mol- 

 ecules and a spherical nucleus. They are probably de- 

 veloped by a folding in of the germinal epithelium. To- 

 ward the internal portion of the ovary the follicles become 



