A Nezv Species of Treiiiatode 9 



a cone-shaped structure with well-marked longitudinal muscle 

 fibers which may be designated as a prepharynx. The small end 

 of the cone connects with the mouth cavity and the large end with 

 the pharynx (fig. 8). 



The pharynx is highly muscular and somewhat unique in being 

 formed of four muscular oval quadrants in place of the two bean- 

 shaped halves which usually form the pharynx in the trematodes 

 (fig. 8). 



The maximum measurements of the pharynx are: length 0.065 

 mm, width 0.083 i''^"'' 5 the minimum : length 0.059 mm, width 

 0.047 '^"''- The mode for the length is 0.059 "^"^ ^o'' 69.2 per 

 cent, and the mode for the width 0.059 ^n"^ ^oi" 61.5 per cent. 

 Following the pharynx is a short esophagus (fig. 8) having a 

 maximum length of 0.207 mm, and a minimum length of 0.047 

 mm, the mode for the length being 0.089 "'"i'' for 16.7 per cent. 

 At the end of the esophagus the digestive tract divides into two 

 caeca which first run outward to approximately the junction of 

 the lateral and second fourths of the width of the animal, then 

 posteriorly and parallel with the lateral borders, thus dividing the 

 body into a median and two lateral fields which contain certain 

 definite organs as described later. The caeca always end 

 posterior to the testes but at a very variable distance from the 

 posterior end, the maximum distance being 0.236 mm, the 

 minimum 0.077 mm and the mode being o. 118 mm and 0.236 mm 

 for 16.7 per cent. In all but four specimens the two caeca were 

 equal in length and in three of the four the right one was the 

 longer (fig. 8). 



The testes (fig. 8) lie in the posterior fifth of the body between 

 the ends of the intestinal caeca, which, as stated above, always 

 end posterior to them. The posterior testis is at a distance from 

 the posterior end of the body varying between 0.154 mm and 

 0.512 mm with a mode of 0.236 mm for 16.6 per cent. They lie 

 very close together one directly behind the other in the median 

 line of the body. As a rule they are nearly spherical in shape, 

 but on contraction of the body of the worm the transverse 

 diameter may become much greater than the longitudinal 

 diameter. In the fourteen specimens the testes of five were 



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