172 GEORGE W. CORNER 



The cells of the other type are those described in my con- 

 tribution of 1915 as "additional cells of the corpus luteum, 

 type 1." They are found throughout the corpus scattered be- 

 tween the larger cells or in small clumps along blood-vessels 

 and connective-tissue septa. They are smaller than the granu- 

 losa lutein cells, having diameters of 15^ to 20/*. In form they 

 are adapted to their interstitial position, being rounded, almost 

 rectangular, or at times compressed into polyangular shape 

 (figs. 23 and 24). Their cytoplasm is either finely granular or 

 contains regular vacuoles so closely packed as to give a foamy 

 appearance. Indeed, in form, size, and in intracellular char- 

 acteristics they present a most striking resemblance to those 

 cells of the theca interna which in the same preparations are 

 still belatedly situated at the periphery of the corpus luteum 

 (fig. 22). Especially in osmium preparations is the similarity 

 so great that one is forced to the hypothesis that we have scat- 

 tered throughout the organ, among the granulosa lutein cells, 

 the multiplied and immigrated cells of the theca interna. In 

 the light of the apparent origin of these cells, it would seem 

 well to give them the name, already established in the litera- 

 ture, 'theca lutein cells,' for though there are certain just reasons 

 for criticism of this term and the name 'granulosa lutein cells' 

 as applied to the other great class of corpus luteum elements, 

 there would seem to be no better names at hand. 



While the cells derived from the granulosa lose their lipoids 

 after the first few weeks, the smaller cells just described again 

 gradually increase their content of osmium-staining lipoids 

 during the span of gestation, and some of them come at last to 

 be laden with these bodies, which, how r ever, do not altogether 

 resemble the lipoid granules of their earlier days (fig. 24). At 

 the end of pregnancy the cells of this type are still present 

 among those derived from the granulosa, apparently having 

 maintained separate identity during the entire term of gestation. 

 Even those which remain for a while in clumps or a definite 

 layer about the periphery are not found to degenerate, but 

 seem to be drawn in among the neighboring granulosa cells as 

 the corpus grows older. 



