SPAWNING BEHAVIOR IN FUNDULUS HETEROCLITUS. 335 



quarters, as is indicated by the fact that they will not feed until 

 they are nearly starving, so it is hardly to be expected that they 

 would spawn under these conditions. I think there can be no 

 reasonable doubt, however, that their spawning behavior closely 

 resembles that of the species described, especially since the ob- 

 served behavior of a representative of another genus, viz., Cyprin- 

 odon variegatns, so closely resembles that of the latter. It is 

 highly probable, judging by the very much elongated anal fin 

 of the male F. niajalis that this fin plays a more important part 

 in clasping the body of the female than does the analogous fin 

 of F. heteroclitus, but the difference, like that in the other details 

 of spawning behavior, is probably one of degree rather than one 

 of kind. 



FUNDULUS DIAPHANUS. 



The following extracts, referring to sexual dimorphism, are 

 taken from Jordan and Evermann's systematic account : 



" Fins not large ; dorsal and anal rather lo\v ; ventral scarcely reach- 

 ing vent in females ; somewhat longer in the males. General color oliva- 

 ceous ; sides silvery. Male with about 20 silvery vertical bars, narrower 

 than the dark interspaces ; female with 15 to 20 transverse bars, shorter 

 than the silvery bands of the male, the interspaces pale ; back sometimes 

 spotted ; young always with black bars ; fins nearly plain." 



In the above description the dark coloration is arbitrarily 

 spoken of as the background on which are superimposed silvery 

 bands, in the case of the male. In the case of the female, on the 

 other hand, the silvery is referred to as background for the some- 

 what narrower dark bars. A casual examination of the figures 

 representing the two sexes (Plate XXVIII., I and 2) will show, 

 I believe, that the dark bars are analagous in both male and 

 female, those of the former simply being considerably broader and 

 a little darker than those of the latter. This greater distinctness 

 of the cross banded pattern in the males is just what we should 

 expect to find if we compare this with the other species examined. 

 The dimorphism in color pattern, however, has not become so 

 pronounced in this case as in the others, and probably represents 

 a more primitive condition. 



The dimorphism in the case of the dorsal and anal fins, although 

 not nearly so marked as in the other species, is still quite evident, 



