520 Mr. W. Nicoll on some 



The suckers are large and muscular. Both are globular. 

 Tlie oral sucker has a diameter of "50 mm., with a circular 

 aperture of "26 mm. 'J'he ventral sucker is situated at the 

 level of the junction of the middle and posterior parts of the 

 body. lis diameter is 1'08 mm. The mouth opens in the 

 oral sucker and is continuous with a large pharynx, there 

 being no pre- pharynx. Tlie pharynx is '24 mm. long. 

 From this the intestine almost immediately divides into two 

 wide branches, which pass down the whole length of the body 

 nearly to the posterior end. 



Tiie genital organs are not distinct, being obscured by the 

 numerous ova which occupy the greater part of the posterior 

 portion of the body. Not far from the ends of tlie intestinal 

 diverticula and contiguous with them are two large somewhat 

 circular testes, about '55 mm. in diameter, placed closely 

 together side by side. The ovary is slightly in front, but 

 hidden by the ova. The vitelline glands are of small extent, 

 being contined to the posterior part of the body, behind the 

 ventral sucker. They are in two rows, one on each side of 

 the body, at some distance from the margin. The genital 

 aperture is situated on a small prominence just in front of tlie 

 ventral sucker. The aperture is elliptical and very distinct. 

 There is apparently no penis-sac. 



The ova are numerous and rather peculiar. They are of 

 two kinds : the younger are in the rear and vary in length 

 from -081 to '095 mm., the breadtli being '040 to •04-4 mm.; 

 the older ova (Pi. XIII, fig. 7) are larger, measuring '106 to 

 '113 mm. X "056 to •062 mm.; they are distinguished from 

 the younger by being lighter in colour and by the presence 

 of a dense, dark, variably shaped spot about •014: to '(JlG mm. 

 in diameter. In many cases this has the form of a cross. 

 It is not difficult to perceive in this the "eye-spots'' of the 

 Miracidium larva developing within the egg-capsule. In 

 this species the "eye- spots''' are particularly large and distinct, 

 80 that they form the most striking feature of the ova at first 

 sight. 



In one specimen several ova were observed lying in the 

 cavity of the ventral sucker. From many of these the 

 capsule had been ruptured, the rupture having taken place in 

 the direction of tlie long axis, so that two equal halves 

 remained, united at one extremity. From this it is probable 

 that the ovum develops completely into the Miracidium 

 within the uterus, and there is a suggestion that the ventral 

 sucker acts as a sort of receptacle for the ova until the capsule 

 is ruptured and the Miracidia are set free. In the absence 

 of lullcr information this can only remain a supposition, and 



