SEX-CHARACTERS IN LEBISTKS RETICULATUS. 



379 



25 mm. The dorsal fin is rounded as is the case in normal females 

 Near the anal orifice a dark black spot can be seen which charac- 

 terizes the mature female in the viviparous fishes and which has 

 been called "puberty spot" by Essenberg (3). The anal fin 

 however has been modified towards the male direction and 

 resembles a gonopod of not fully developed males, (Fig. 12). 

 The colorations are more like those of the male than those of a 

 female. The black spot found in the tail region is present in the 

 hermaphrodite as well as the orange line on the lower margin of 

 the tail fin. Compare Fig. 10, which is a normal female, Fig. n, 



FIG. 13, 



a normal male, and Fig. 12, the hermaphrodite. On dissection 

 a fully developed ovary containing almost completely formed 

 embryos was discovered. 



The gonad was embedded and sections, 8 microns in thickness, 

 made. Material was stained in Heidenhain's iron-hematoxylin 

 and Mallory's connective tissue stain. 



The histological picture corroborates all the features that were 

 observed by the unaided eye, that is, a well-developed ovary with 

 embryos almost ready to be born. Besides all along the ovary, 

 gradually tapering, was found a well developed testicle (Fig. 13). 



