268 Mr. W. Nicoll on the 



in tlic following respects : — The suckers are proportionately 

 larger and the oral sucker is distinctly greater than the 

 ventral, their diameters being respectively '068 mm. and 

 •059 ram. The ventral sucker is situated in front of the 

 middle of the body. The pharynx is of the same size as that 

 in M. gratiosum, but the prepharynx is shorter. The oeso- 

 phagus is about the same length in both ; the diverticula are 

 here distinctly shorter, not extending beyond the level of 

 the ventral sucker. They arc straighter and wider^ and are 

 only 1^ times the length of the oesophagus. 



The ovary is the same as before, but always slightly to the 

 right and somewhat smaller. The condition of the uterus is 

 also similar ; the ova are quite as numerous but smaller, 

 measuring only -OIS-OIO x -OOQ-OIO mm. The testes are 

 further forward, the right testis being almost contiguous 

 with the ovary and the vesicula seminalis. Their long axes 

 are always, so far as I have observed, directly transverse, 

 and they are not overlapped by the uterus to any great 

 extent. The vesicula seminalis is much larger, extending 

 back as far as the anterior border of the right testis. The 

 course of the vagina is distinctly Z-shaped. 



Maritrema humile, sp. n. 



This was found in large numbers in the intestine of 

 Tot anus calidris. It is a very small species, measuring only 

 •28-'40 mm. in length, with a maximum breadth of •12- 

 •16 mm. The cuticle is almost entirely covered with scales. 

 Unlike the other two species, it has the oral sucker less than 

 the ventral, the diameters being respectively •025--031 mm. 

 and •030-034 mm. The ventral sucker is very nearly in 

 the middle of the body. The pharynx measures 019 x -010 

 ram., and the prepharynx is about the same length. The 

 oesophagus is •04-'05 mm. long, or nearly ^ of the body- 

 length, while the diverticula are almost twice as long. The 

 latter are dilated, wide apart, and only reach the level of the 

 anterior border of the ventral sucker. 



The ovary, uterus, and yolk-glands are the same as in the 

 other two species. The ova are still smaller than those of 

 M. lepidum, being only -OlG-'OlSx -OOS-'Oll mm. The 

 testes are almost entirely enveloped by the uterus and their 

 position is not obvious. They are symmetrical, transversely 

 oval, and further back than in M. lepidus. The vesicula 

 seminalis is a comparatively large structure, and the cirrus- 

 pouch has exceptionally thick walls. It measures '093 X "032 

 mm., and occasionally overlaps the ventral sucker to a con- 

 siderable extent. 



