244 DR. K. T. LEIPER ON [Feb. 1 



surface of the body, passing over the fundus of the excretory 

 vesicle and opening 0*53 mm. in front of the excretory pore. 



The excretory vesicle is pear-shaped, measures 0-7 mm. in 

 length by 0*3 mm. in greatest breadth at the fundus, tapering 

 gradually as it passes backwards to terminate in the excretory 

 duct, Ol mm. in length, that opens on the dorsal surface in 

 the middle line and at the level of the centre of the ventral 

 sucker. 



The median longitudinal serial section of the parasite from 

 which the above measurements were all derived measured 3 - 5 mm. 

 in length, 1 mm. at the level of the dome of the ventral sucker, 

 065 mm. at the level of the genital pore dorso-ventrally. 



8. Paramphistomum minutum, sp. n. (Text-fig. 32.) 



Among the specimens of P. buxifrons collected from the stomach 

 were seen a number of very minute forms distinguished by the 

 absence of pigment. These were at first regarded as young forms 

 of P. buxifrons, but on cutting serial sections of two or three of 

 them I was surprised to find that they were sexually mature, 

 and that in each the uterus contained eggs. In other respects, 

 especially in the structure of the genital atrium, they differed 

 markedly not only from P. buxifrons but also from the other 

 amphistomes. 



Form, etc. — The body is oviform in shape and measures 2 # 7 mm. 

 in length by - 7 mm. in thickness. The ventral sucker lies sub- 

 terminally and measures 0'66 mm. in diameter ; its musculature is 

 028 mm. thick at the dome, its cavity is 0*46 mm. wide, and its 

 aperture is 0'32 mm. The cuticfe is smooth and of uniform 

 thickness on the dorsal and ventral surfaces. There are a few 

 papilla? around the mouth. 



The pharynx is globular in shape, measuring 0*45 mm. long by 

 0*3 mm. broad, with a musculature of 0*14 mm. at its thickest 

 part. There are no pharyngeal pouches. 



The oesophagus is 0*1 8 mm. in length and has a diameter of 

 0*08 mm. The bifurcation of the gut lies behind the genital 

 atrium, which opens at the level of the junction of the oesophagus 

 and pharynx. The two gut-branches have a width of about 

 0*1 mm., and end after a tortuous course just anterior to the 

 ovary. 



The genital pore opens at the junction of the anterior fifth with 

 the rest of the body, immediately behind the pharynx. 



The genital atrium has a well-developed muscular wall Ol mm. 

 in thickness and sharpty delimited from the surrounding par- 

 enchyma. 



The testes are relatively very small in size, oval in shape, and 

 measuring only 0*2 mm. antero-posteriorly by 0*15 mm. dorso- 

 ventrally ; they lie one in front of the other in the middle line of 

 the body, but nearer the ventral than the dorsal surface, and their 

 longitudinal axis is placed at an angle of 30° ventral to the median 

 line of the body. If the body length be divided into two equal 



