212 



S. J. JOHNSTON. 



just behind the anterior edge of the ventral sucker, and 

 some distance in front of the bifurcation of the intestine. 

 The pear-shaped cirrus sac lies dorsal to the ventral sucker,, 

 reaching nearly to its posterior end. The testes lie in the 

 anterior half of the body and overlap a little into the 

 posterior half. They are slightly lobed elongated bodies 

 about equal in size, the anterior measuring 0*815 x 0*582 

 mm. and the posterior 0*873 x 0*524 mm. 



The spherical ovary is much smaller and lies some dis- 

 tance (0*388 mm.) in front of the testes. It is median in 

 position. The large gland of Mehlis lies just behind it. 

 The uterus exhibits only a few transverse coils and then 

 runs forwards in a wavy course to the genital opening. 



The yolk-glands are confined to a narrow lateral field on 

 each side, not extending inwards beyond the intestinal 

 limbs and reaching from the ventral sucker to the extreme 

 posterior end. 



The follicles are very numerous, small, and oval, 0*05& 

 x 0*027 to 0*08 x 0*032 mm. 



The eggs are more than twice as long as broad, 0*096 x 

 0*043 to 0*107 x 0*048 mm. 



P. acuminatas differs from P. bilobus, Rud., which i& 

 parasitic in Ibis falcinellis and Plabalea leucorodia in the 

 shape of its body and narrower collar, in having the genital 

 pore situated in front of the intestinal fork instead of 

 behind it as it is in P. bilobus; also in having the gonads 

 further apart, in the narrower fields of its yolk-glands, in 

 the fewer coils of the uterus and in its much narrower eggs- 



The Australian form differs also from P. consimilis, Dietz, 

 found in Geronticus albicollis, in Brazil, in its acuminate 

 posterior end and more slender form; in having much 

 larger spines on the collar, a smaller oral sucker, narrower 

 yolk-gland fields and narrower eggs. The position of the 



