324 



ME. O. S. WEST OK A NEW SPECIES OE DISTOMUM. 



quite constant, being only just posterior to the ventral sucker in 

 some, and in others a considerable distance posterior to it. The 

 penis was protruded in most of the specimens as a very con- 

 siderable papilla. 



The excretory vesicle extends up the centre of the body 

 amongst the folds of the uterus for a considerable distance, and 

 is seen in any transverse section of the posterior end of the body 

 (fig. 5, e.v.). 



EXPLANATION OF PLATE XT. 



Fig. 1. Distomum Philodryadum, n. sp. Animal viewed from the ventral 

 surface, showing most of the internal anatomy. 



2. Part of another animal, showing a difference in position of the genital 



pore. 



3. Transverse section through the region of the ventral sucker ; the animal 



had the uterus greatly distended with eggs. 



4. Transverse section a little posterior to the ventral sucker. 



5. Transverse section through the posterior end of the body. 



6. Section showing the ectoderm, mesenchyma, and some of the muscles. 



7. Transverse section through a nerve-cell. 

 S. Longitudinal section through a nerve-cell. 



Figs. 9, 10. Two ova. X 520. 



c.p. = cirrus pouch. 



eo. = ectoderm. 

 e.v. = excretory vesicle. 

 g.p. = genital pore ( c5' or $ ). 

 i. = intestine. 



m. = mesenchyma. 

 m.l. = longitudinal body-muscles. 

 m.n. — nuclei of mesenchyma. 

 m.o. = oblique body-muscles. 



n. = nerve-cell. 



oe. = oesophagus. 



ov. = ovary. 



p. = penis. 

 ph. = pharynx. 

 r.s. = receptaculum seminis. 

 s.o. = oral sucker. 

 s.v. — ventral sucker. 

 sp. = spines. 

 ty and ^2 = testes. 



u. — uterus. 

 v.d. = vas deferens. 

 v.s. = seminal vesicle. 



vt. = vitellaria. 



