ECTOPARASITIC TREMATODES. 285 



shaped mass. The latter was probably mistaken for a sucker by 

 Monticelli ; for I find an exactly similar arrangement in A. 

 Lobianchoi, a few specimens of which have been kindly sent me 

 in exchange by Prof. Monticelli. 



The oesophagus is exceedingly short, and the simple intestinal 

 branches terminate a little in front of the centre of the sucker. 



The terminal portions of the genital ducts could not be 

 satisfactorily made out in the single specimen at my command ; 

 and although the results of my observations differ in some import- 

 ant points from those of Monticelli, I believe they are in the 

 main correct. 



The ovary is a spherical body lying in the median line at 

 the hind end of the anterior one-third of the total length of the 

 body. The oviduct starts from the anterior end of the ovary and 

 presents an enlargement at the outset, which is perhaps the ootyp. 

 If this is so, then the whole remaining portion of the duct 

 must be called the uterus ; this undergoes some convolutions, and 

 proceeding obliquely towards the right side, opens into the hind 

 end of a shallow genital atrium in the margin of the body, in the 

 constriction mentioned above. There are about 37 testes as seen 

 from tiie ventral side ; and the vas deferens starts on the right 

 side, between the ovary and the intestine. It then proceeds for- 

 wards, and just behind the intestinal arc, describes a loop, and 

 after undergoing some additional convolutions, opens finally into 

 the genital atrium at its front end. There are several enlarge- 

 ments in the course of the vas deferens. On the right side of 

 the body just in front of the excretory vesicle there is another 

 cavity of a spherical form. This, I believe, is the seminal re- 

 ceptacle, and the canal proceeding anteriorly from it and open- 

 ing into the genital atrium between the uterus and the vas 



