402 J. STAFPORD, 



3. Monostomuni atniuvi n, sp. 



The only Distomes I have observcd in the cat-fisli are 2 species 



— oiie in the eye and the other in the liver of the young fishes, about 

 au inch and a quarter long, that we use from which to prepare 

 serial sections. This Trematode occurs in the swira-bladder of the 

 adult cat-fish (Ämiurus nehulosus). Since it possesses but oue sucker 



— the oral — it falls in the group Monostomidae ; and the name 

 Monosfomum amiuri, by which I have chosen to designate it, can not, 

 so far as I at present see, prove either vague or conflicting. 



Monosfomum amiuri is a worm about 5 mm long and 2,25 mm 

 broad. It is much flattened and is broadest in its posterior two thirds, 

 the anterior third narrowing towards the mouth-sucker. The dorsal 

 surface of the living worm reminds oue, in its pigmented appearance, 

 of some of the free-living fresh-water Planaria. The colour is largely 

 due to the Contents of the intestiue and to the numerous eggs. It is 

 somewhat dark, not unlike the inner membrane of the air-bladder on 

 which it rests, but with two longitudinal, rusty stripes. The living 

 animals are very soft bodied, inactive creatures. 



The integuraent bears a cuticle and is apparently very thin ; the 

 sub-cuticular and glandulär parts seem to have a similar structure to 

 the sanie parts of the Distomes with which I am most acquaiuted. 



The intestinal System begins with the mouth whose thick muscular 

 walls form the oral sucker. This is succeeded by a muscular pharynx 

 after which follows a narrow Oesophagus. The latter gives rise to 

 two lateral intestinal caeca, exteuding as broad tubes to near the 

 posterior end of the body where they end blindly. 



The nervous System I have not yet undertaken to follow. 



Owing to the unfavourableness of the living worm, only the pos- 

 terior unpaired part of the excretory System has been made out. 



The reproductive System is of the usual complex type for this 

 group of animals. There is no sexual dimorphism, each individual 

 being dioecious. The genital glauds of the male sexual orgaus — the 

 testes — are situated most posterior in the body, between the median 

 expulsion tube of the excretory System and the ends of the intestinal 

 caeca. Vasa deferentia rise out of their anterior euds and proceed, 

 by a direct course, to near the middle of the animal where they meet 

 in the vesicula seminalis. The latter runs forwards and opeus by a 

 muscular penis on the ventral surface of the worm, about one third 

 from its anterior end. The structure of this portion of the genital 

 Organs I have not satisfactorily made out. The female organs include 



