272 R. R. HUMPHREY 



Whitehead, R. H. 1904 The embryonic development of the interstitial cells of 

 Leydig. Am. Jour. Anat., vol. 3, p. 167. 



1908 A i)cculiar case of cryptorchi.sni and its bearing upon the problem 

 of the function of the interstitial cells of the testis. Anat. Rec, vol. 

 2, p. 177. 



1912 A microchemical study of the fatty bodies in the interstitial cells 

 of the testis. Anat. Rec, vol. 6, p. 65. 



PLATE 1 



EXPLANATION OF FIGURES 



8 Testis of Necturus July 31st; cephalic portion tangential section, cutting 

 the lobules in cross-section. Shows the distention of the lobules characteristic of 

 this period. The lobules are filled with spermatocytes I. Bouin's fluid; 8^; 

 copper hematoxylin. X 120. 



9 Portion of above section under higher magnification, to show the inter- 

 lobular nuclei of elongated form. X 300. 



10 Testis of Necturus October 7th; caudal region. Lobules cut in cross- 

 section. Compare with figure 8 as to shape of the lobules, from which now the 

 mature spermatozoa have been partially extruded. Groups of spermatozoa 

 within the lobules are deeply stained. A mitotic figure is seen in the inter- 

 stitial-cell sheath, near the upper edge of the photograph. Zenker's fixation; 

 6(1] iron hematoxylin. X 154. 



11 Same section as in figure 10, but showing the lobules cut in longitudinal 

 section. Interlobular tissue greatly increased in prominence; nuclei less flat- 

 tened than in figures 8 and 9; mitotic figures abundant (one appears near bottom 

 of photograph). X 120. 



12 Testis of Necturus October 30th; tangential section of caudal region. 

 The lobules, which are here cut in cross-section, contain only degenerating 

 Sertoli cells and are surrounded by prominent epithelioid rings of interstitial 

 cells. Regaud's fixation; copper hematoxylin; 5^. X 154. 



13 Testis of Necturus April 8th; extreme anterior portion. Shows consider- 

 able lipoid, blackened by osmic acid, within the degenerating lobules, but only a 

 few scattered interstitial cells (as at x). Bensley's fixation; 5m ; nostain. X 120. 



