208 H. H. NEWMAN. 



Roule's paper, being simply a preliminary statement, is too 

 inadequate to furnish the basis for a detailed discussion, yet it 

 might be well to point out that the Poeciliidae, a family rather 

 closely related to the Cyprinidae with which Roule worked and 

 about which there can be no suspicion of normal hermaph- 

 roditism, exhibit conditions closely parallel to those cited by 

 Roule. 



Let us take, for example, the state of affairs in Fundnlus 

 majalis. Here the mature males are, on the average, consider- 

 ably smaller than the mature females ; yet the largest of the 

 males often surpass in size the smaller sized females. Again, 

 the very smallest sexually mature individuals are always males 

 and the very largest are always females. The males also mature 

 distinctly earlier in the season than do the females. All of these 

 facts attest the precocity and dwarfing of the males. 



In view of the fact, however, that in F. majalis there is a 

 very pronounced sexual dimorphism that begins to make itself 

 apparent in very young and immature fish, it becomes certain 

 that all individuals are unisexual throughout life. The individual 

 whose discovery gave occasion for this paper, is the only ex- 

 ception to this rule that has come under the observation of the 

 writer although he has examined thousands of specimens of this 

 and allied species during the last three years. 



In order that the reader may more readily understand the 

 account of this rather remarkable case of hermaphroditism it 

 seems necessary to recapitulate certain facts concerning the 

 sexual dimorphism and spawning behavior of Funduhis majalis, 

 a subject treated extensively in former papers (Newman, '07 and 

 '08). , 



In F. majalis the sexes differ in the following particulars : 



1. The females are larger, on the average, than the males. 



2. The body color pattern of the two sexes is entirely differ- 

 ent ; that of the male consisting of distinct transverse bands 

 running from back of the head to near the base of the caudal 

 fin (see Fig. i) ; that of the female, on the other hand, consist- 

 ing essentially of well-marked longitudinal stripes, perfect an- 

 teriorly and merging posteriorly into a few cross bands like those 

 of the male (see Fig. 4). 



