BY S. J. JOHNSTON. 341 



The above columns show that Alesocwliu/ti agrees with the 

 jjicrocoeliiuse in the position of the ovary behind the testes. 

 But in these worms, as pointed out above, the position of the 

 ovary is very variable, and cannot be looked upon as of 

 dominant importance in referring the genus to its subfamily. 

 The position of the genital pore in the median plane is differ- 

 ent, but not strikingly different, in the two subfamilies in 

 question as well as in MesocoeUum, while the length of the 

 intestinal limbs in AlesocwUu/n, is intermediate between that 

 in the Dicrocoeliinae and the Brachycoeliince. In the charac- 

 ter of the integument, in the relative size of the suckers, in 

 the character and disposition of the testes, and in the disposi- 

 tion of the yolk-glands, Mesocahuni agrees with the Brachy- 

 cceliinae rather than with the Dicrocoeliinae. And, lastly, let 

 us look at the hosts of these worms. Mesoaelium, occurring 

 in the intestine of Amphibia, is likely, when the above charac- 

 ters are taken into consideration, to be more closely related to 

 the Brachycoeliinae, occurring in the intestine of Amphibia, 

 than to the Dicrocoeliinae, occurring, as they do, for the most 

 part, in the liver and gall-bladder of mammals and birds. 



In regard to the position of Hoploderma Cohn, I am in- 

 clined to think, from the evidence available, that it should be 

 placed along with Brachyca'luiin and MesocjeUum in the 

 Brachycoeliinse. But one should not lay too much stress on 

 such unsatisfactory material as that furnished by worms taken 

 from old spirit-specimens. 



Genus Pleurogenes Looss, 1896 b. 

 Pleurogenes freycineti, .sp.n. 



(Figures 16, 77-80.) 



Diagnosis. — Body oval, narrower end anterior, 1'45 mm. long, 

 089 mm. broad; oral sucker subterminal, 0-202 mm. in diameter, 

 ventral sucker in middle of body, 0-176 mm. in diameter; ratio oj 

 former to latter, 7:6. Body covered by flat spines or scales with 

 their points bluntly rounded, nuinher and size hardly less at 



