PARASITES OF THE SALMON OE THE TAY. 



149 



Entozoa. — If tlie search for food in the digestive system of the 

 clean sahnon and grilse was only rarely rewarded by success, 

 certainly tliat for entozoa was more fortunate. There was scarcely 

 a single fish which did not contain some of the following species, 

 and many had them in abundance. The first of these I shall de- 

 scribe (fig. 1, a, h) is seldom or never absent throughout the entire 



Kg. 1. 



series of grilse and salmon. It is a minute creature, of grega- 

 riniform aspect, which squeezes its gelatinous body hither and 

 thither amongst the granular debris and oil-globules of the duo- 

 denum and pyloric cseca. In its interior are numerous globules 

 and granules, and a larger spherical body, wliich, when the animal 

 is flattened between the glasses, gives it the aspect of having a 

 sucker. One end is generally darker from the accumulation of 

 the granular contents. Besides the shapes depicted in the draw- 

 ing, this creature very often assumes an hourglass aspect from a 

 central constriction. One of the chief habitats of this gregarini- 

 form animal is the pyloric CEeca, where it has been found amongst 

 the dry mucus even at the tip of one entirely blocked up by the 

 coils of a Bothriocephalus. It is in all probability a stage in the 

 development of some higher parasitic form. 



Occurring in the greater number of the specimens of both 

 grilse and salmon is Distovia varicum (Rud.), {Fasciola varica 

 O.F. Miiller, Zoologia Danica, p. 43, plate 72). Almost with- 

 out exception, this species occurred in the stomach of the 

 salmon, imbedded amongst the tenacious mucus, or else at the 

 border of the latter at the commencement of the organ. They 

 varied in number from one or two up to twenty -five or thirty in 

 extreme cases, and they were also diversified as regards size. 

 Miiller in the above work observes that he met with five in the 

 stomach of a salmon, and Eudolj^hi states that it is rare. This, 



