325 H. H. NEWMAN. 



Text Plate II. It is also interesting to note that the best de- 

 veloped and most frequent contact organs occur where the pres- 

 sure in spawning must be the greatest, namely between the dorsal 

 and anal fins and on these fins at or near their bases. In each 

 case the maximum distribution seen in the males collected is 

 shown in the figure. The stippling is closer in regions where 

 the contact organs are thickest and best developed, and more 

 open where the latter are more scattering and less well developed. 

 No attempt has been made in these diagrams to represent actual 

 numbers or sizes. 



' .! 

 I , 





TEXT PLATE III. 



Showing scales with contact organs, X I2 - 



1. Scale from the side of a large male F. majalis. 



2. Scale from a corresponding part of the body of a large female F. majalis, 



3. Scale from the lateral line region between the dorsal and anal fins of a spawn- 

 ing male Cypriitoi/on variegalns. 



4. Scale from a similar location of a spawning female Cyprinodon variegatus. 



An examination of a considerable number of males reveals the 

 fact that only those in spawning plumage possess contact organs, 



