REPRODUCTIVE SYSTEM OF FREE-MARTINS 459 



had not been preserved carefully for microscopic study.) The 

 whole duct is smaller in diameter than the duct of a normal female 

 of the same size. 



b. Condition in the free-martin 



The gonad of the free-martm 19, on microscopic examination, 

 is found to consist of a central, rather dense mass of deeply 

 staining cells, surrounded by a layer of cells less dense than the 

 central mass, figures 4 and 5. The outer structure is albuginea, 

 similar to that of the testis, but it is not arranged in definite 

 layers as in the normal cf T19. In the anterior part, the cen- 

 tral mass shows two divisions. The smaller one, round in 

 cross section, is the rete. This is easily traced from its con- 

 nection with the glomeruli in the Wolffian body, into the gonad 

 which it penetrates almost at the anterior apex, figure 4. A 

 short distance posterior to its entrance into the central mass 

 of the gonad it becomes scarcely distinguishable from the rest 

 of the mass, figure 5. The rete is not differentiated into cords. 

 The remaining portion of the central mass of the gonad partly 

 surrounds the rete. It is an undifferentiated mass of cells, but 

 represents the medullary cords. A very few germ cells are 

 found. These are in Schoenfeld's growth stages c, d and e. 

 Interstitial cells cannot be distinguished. A single layer of 

 peritoneum covers the whole gonad, as in the testis. Although 

 the gonad is much smaller than those of the normal cf and 9 

 studied in comparison with free-martin 19, the Wolffian body is 

 of normal size and structure. The Wolffian tubules and Mal- 

 pighian bodies in 7.5 cm. free-martin 19 are as numerous as 

 they are in the 7 cm. d^ NIO and 7.3 cm. 9 N8, and more 

 numerous than in its twin, the 8 cm. d^ T19 and in the 8.3 cm. 

 9 N7. 



The Wolffian duct of the free-martin is normal. The Mtil- 

 lerian duct, on the other hand, is abnormal. At its anterior end 

 it is like the Miillerian duct of the normal male twin 19. The 

 connective tissue rod lies in the normal position of the Miillerian 

 duct, but the epithelial duct which it encloses is discontinuous. 

 The lumen is present only at irregular intervals and even the 



