D. W. CrTI^KH AND L. DoNCASTER 73 



EXPLANATION OF PLATE XX. 



Fig. 1. Portion of testis of normal cat ('2 mm. immersion lens). The amount of 

 interstitial tissue represented is rather unusually large ; c.ii. light nuclei of interstitial 

 tissue ; d.ii. darkly-stained nuclei of interstitial tissue ; d.g. secretory granules. 



Fig. 2. Portion of testis of tortoiseshell torn cat, low power. 



Fig. i. Similar portion drawn with 2 mm. immersion lens. Lettering as in Fig. 1. 



Fig. 4. Portion of testis of hermaphrodite pig (2 mm. immersion lens). 



Fig. 5. Portion of human retained testis, showing the thickened walls of the tubules, 

 but otherwise similar to the preceding specimens. The fibrous structure uf the 

 interstitial tissue found in some cases, is not seen in this specimen. 2 mm. immersion. 



Fig. 6. Portion of testis of hen-feathered cock. 2 mm. immersion. •;.(. interstitial tissue. 



