414 J- STAFFORD, Some undeseribed Trematodes. 



plaiuly in two halves, neither are they confined to the lateral regions, 

 but lie also across the ventral surface of the iutestine and ovary. 



I shall here mention a few of the ways in which the worms I 

 have difter from the figure and description by Looss. If his figure 

 is characteristic, and if my examples are normal, then there still 

 remains the question whether the differences are of more than varietal 

 importance. 



Leugth : breadth = 3:2 instead of 2:1. 



Broadest at middle and posterior. 



Posterior end broad and indented instead of drawn out and pointed. 



Ventral sucker rather larger than oral sucker instead of the reverse. 



Oesophagus shorter than would appear in the figure by Looss. 



Ovary inside instead of outside the right caecum, and with an 

 irregulär lobed shape instead of rounded. 



Uterus in folds transversely instead of longitudinally. 



Eggs without a gelatinous coat. 



Vitellaria extending over a ruucli greater surface and not distinctly 

 separate, instead of being confined to tvvo separate, small districts on 

 each side of the Oesophagus. 



Occur encapsuled in the liver instead of free in the proximal 

 portion of the small intestine. 



'7. JPolystotnum oblonguni Wright. 

 In the paper by Wright, already referred to, he figures and de- 

 scribes a new species from the urinary bladder of the rausk turtle and 

 expresses the opinion that Polystomes would be found in the mouth 

 of the painted turtle and of the snapping turtle. I have found a 

 Single specimen on the palate of the first named turtle and I feel 

 tolerably certain that it is the same species as the one described by 

 Wright under the name Polystomum oblongum. I souglit to learn as 

 mucli as possible from the Single animal and accordingly studied it 

 first alive and afterwards killed and sectioned. As miglit be expected 

 under such treatment neither method would give its best results. 



Explaiiatioii of tlie Plate. 



Fig. 1. Distomum peJagicum. »Surface of the ocean. Real length 0.92 mm. 



Fig. 2. Monostonmm amiuri. Swim-bladder, catfisb. Leugth 5 mm. 



Fig. 8. Distomum hospitale. Iutestine, newt. Leugth 4 mm. 



Fig. 4. Distomum quietum. lutestiue, frog. Length 2.8 mm. 



Fig. 5. Distomum chehjdrae. Intestine, snapping turtle. Leugth 6 mm. 



Fig. 6. Distomum angustum. Intestine, painted turtle. Length 3.15 mm. 



