385 



(ii) A wider irregular transverse spot, at 

 thirty-six per cent, length. Occasionally. 



(iii) The largest of the spots an irregular 

 transverse area, sixty-three per cent, length. Not 

 always present. 



(iv) A very inconstant central bright speck 

 at eighty-three per cent, length. 



Fig. 87. F bancroffi, Embryo shewing sheath ; F. perstans, 



Embryo (sheathless) ; F. bancrofti (Embryo), prepuce, and 



fang (above) ; F. perstans (Embryo), fang (below) 



6. They are readily distinguished from the 

 embryos of F. oszardi by their blunt tails. 



7. The observations of Firket and Christy 

 point to the fact that there is more than one 

 species of -F. perstans. 



F. ozzardi : — 



I. Length, one hundred and seventy-three 

 to two hundred and forty m by four to five m. 



A I 



