EXPLANATION OF PLATE III. 



(See page 92). 



Fig. 1. — Penis when first extruded. 



2. — Penis with frilled edge appearing. 



3. — Penis fully expanded. 



4. — The expanded organs of a paired couple commencing 



to intertwine. 

 5. — Knot formed after intertwining. 

 6. — The two upper whorls of ' knot ' expanding horizontally 



during copulation. 

 7. — View of same from above. 

 8. — The two upper whorls of ' knot ' curling different ways 



during copulation. 

 9. — Position of pair in copula, showing usual appearance of 



' knot ' where both whorls curl downwards. 



All the figures are natural size. 



