THE STRUCTURE OF FREE-MARTIN GONADS 97 



it is homogeneous throughout, in a few others it is extensively 

 vacuolated, while in the majority of the cells the cytoplasm con- 

 tains bundles of rod-like structures. Owing to the poor fixation 

 of the gonads from cases 44 and H-46, a detailed description of 

 the interstitial cells cannot be given. 



The organization of the sexual cords has reached its highest 

 degree of transformation in the male direction, so that a major- 

 ity of the sexual cords are definite convoluted seminiferous 

 tubules. In H-37 the tubules are scattered more or less evenly 

 throughout the sex-cord region, but in H-46 and 44 there are 

 areas which are free from tubules. They appear as areas of 

 apparently undifferentiated tissue (fig. 10, ut), but on closer 

 examination it is seen that some organization has occurred. 

 Among the abundant connective-tissue fibers are slender cords 

 of sexual cords, a few of which resemble miniature seminiferous 

 tubules and others which resemble medullary cords, and inter- 

 stitial cells. Owing to the close resemblance of these undifferen- 

 tiated areas to the sex-cord region of some of the foetal free- 

 martin gonads, they are regarded as areas which retain the 

 embryonic structure. 



The seminiferous tubules appear to be as much coiled as the 

 normal tubules of the testis, but they are not as closely packed 

 together nor as large. The tubules of H-37 (fig. 11), which 

 resemble to a close degree the tubules of the normal testis of the 

 adult, are, however, only half as large in diameter as the latter 

 (adult 0.225 mm.) (fig. 13, s). The tubules of cases 44 and H-46 

 (fig. 12) are about one-fourth the diameter of a normal tubule of 

 the adult testis. 



Each tubule is enclosed by a much thickened membranous 

 wall, which is composed of a number of concentric lamellae of 

 connective-tissue fibers. The innermost lamellae are very 

 closely arranged and hyahne-Uke, giving the appearance of a 



Fig. 13 The junction of a seminiferous tubule and a straight tubule (tubulus 

 rectus) from the testis of an adult bull, Bos 2. s, seminiferous tubule showing 

 spermatogonia, maturating germ cells and spermatozoa; si, lumen of straight 

 tubule; ss, Sertoli-cell syncytium free from germ cells; te, abrupt beginning of 

 the epithelium of the straight tubule; w, connective-tissue wall of the tubule. 

 X240. 



