1910.] 



ENTOZOA OF THE HIPPOPOTAMUS. 



241 



The cuticle is smooth and there are no papillae surrounding the 

 mouth. 



The pharynx is oval, and measures 1*1 mm. in length by 1 mm. 

 in transverse diameter, and its musculature has a thickness of 

 0*4 mm. There are no pharyngeal pouches. 



The oesophagus is S -shaped, measures - 9 mm. in length by 

 02 mm. in breadth. The musculature of its wall is only slightly 

 developed. 



The bifurcation of the gut lies anterior to the genital pore on a 

 level with the posterior fourth of the pharynx. 



The gut-branches have a width of 1 mm. and end blindly upon 

 the sides of the ventral sucker at the level of its lower lip. 



Text-fisr. 30. . 



Paramjphisf.omum giganbocotyle. Median longitudinal section. 



The genital opening lies on the ventral surface midway between 

 the mouth and the anterior limit of the ventral sucker. The 

 genital atrium is slit-like. Its wall is strengthened by some 

 thickening of the subcuticle. 



The testes, two in number, are deeply incised transversely so as to 

 give to each the appearance, in some sections, of two distinct bodies. 

 Otto makes the statement that there is only one testicular mass. 

 The testes are almond-shaped : they lie in contact, one behind the 

 other, with their longitudinal axis, 1*1 mm., at right angles to 

 that of the body. The maximum antero-posterior measurement 

 is 0*5 mm. 



The yolk-glands consist of numerous very small follicles 

 scattered throughout the parenchymatous tissue on the outer 

 aspects of the voluminous gut-branches. 



Proc. Zool. Soc— 1910, No. XVI. 16 



