American Eepresentatives of Distomnm varie£»'atnm. 903 



come to lie betweeii the lateral hunclies. and tliis may occur at 

 botli ends of the series. Sometimes one or two groiips of one side, 

 at the posterior end, are lacking, and their place may be taken 

 by bunches connected with the longitudinal duct of the opposite 

 side. The number öf follicles in a bunch is variable and difficnlt 

 to count, but I have seen from ten to thirty, and the follicles 

 appear to be rather small. 



The Uterus has characteristic long-, black, lateral loops, out- 

 wards from the intestinal caeca and extending* from the posterior 

 end to near the pharynx, as well as two median bands, the dorsal 

 li^ht coloured. reaching: from the ovarj?' to the posterior end, the 

 ventral running the wliole lenght of the body to the genital pore 

 close under the mouth-sucker. 



The egg, in both fresh and preserved specimens, varies a little 

 about •022 X '017 mm. Ripe eggs are of a uniform, light-brown 

 colour, Short- elliptical, with ends equal. or more oval with a lid at 

 the small end and. offen, a little more convex on one side than the 

 other. 



Young Worms, from half a millimetre length upwards, can 

 easily be recognized as belonging to the species. The smallest, that 

 I have mounted, occurred in the lung of a bull-frog, along with 

 large ones of the same kind. It measures "58 mm by *18 mm. The 

 mouth-sucker is "08 mm and the ventral "06 mm in section — the 

 latter behind the middle of the length of the animal. The caeca 

 are relatively large and filled with pigment — decomposed blood 

 corpuscles — and the rudiments of genital organs are present. 

 Missing some intermediate stages in which there is nothing special 

 to note and Coming to one 1-33 mm in length, the ventral sucker 

 is anterior to the middle and is less than half the diameter of the 

 mouth-sucker. Ovary and testes are enlarged and the oviduct can 

 be traced — by its contained pigment globules — from the middle 

 of the animal backwards; the two lateral loops are present, but 

 very short; the long median part to below the mouth-sucker, and 

 in fact all with the exception of the small origin from the ovary, 

 is ventral in position and almost straight. At 2 mm length the 

 lateral loops reach nearly to the middle of the body, and at a 

 length of 2-75 mm the animal has taken the form of the adult. 



