TREMATODES FROM FISHES — ^LINTON 169 



of the intestines, giving the appearance of distinct, nearly translucent 

 bodies. 



One, collected August 7, 1906, length, 2.38 mm. Measurements in 

 balsam: Length, 1.54 mm.; breadth, near anterior end, 0.10 mm., 

 at level of ventral sucker, 0.18 mm,, maximum, 0.29 mm. ; oral sucker, 

 length, 0.054 mm., breadth, 0.051 mm.; ventral sucker, length, 0.09 

 mm., breadth, 0.10 mm. ; length of neck, 0.16 mm. 



From round herring: One, collected July 25, 1908; slender, white, 

 very active, cylindrical before compression under the cover glass. 

 The anterior part of the postacetabular region opaque, white by 

 reflected light, yellowish brown by transmitted light. The posterior 

 half of the postacetabular region contained eight pairs of transparent 

 bodies, which are to be interpreted as being caused by somewhat 

 regular constrictions of the walls of the voluminous intestinal rami. 

 By reflected light they have the appearance of windowlike spaces 

 occupied by a thin, transparent membrane ; by transmitted light they 

 have the appearance of thickish, bladderlike bodies with more or less 

 lobed or crenulated outlines. The lobed character disappeared as the 

 worm was kept under observation. The mouth is terminal. The 

 anterior end was slightly invaginated. The surface was crossed by 

 exceedingly fine wavy lines. Measurements, life : Length, 2.10 mm, ; 

 breadth, 0.24 mm. ; diameter of ventral sucker, 0.09 mm. 



Two (U.S.N.M, No, 8408) , collected September 17, 1912. Measure- 

 ments, life : Length, 2.24 mm. ; maximum breadth, 0.36 mm. ; oral 

 sucker, length, 0.084 mm., breadth, 0.056 mm.; diameter of ventral 

 sucker, 0.11 mm. The voluminous intestines were represented by five 

 or six pairs of bladderlike structures at the posterior end of the body, 

 anteriorly they continue as smaller, laterally placed bodies with finely 

 granular contents. It was noted that at the posterior end beneath 

 the cuticle there was a layer of nucleated cells. These specimens 

 were stained and mounted in balsam but are not satisfactory. The 

 10 posterior divisions of the intestine are filled with a structureless 

 material that does not take the stain. In the postacetabular region, 

 which is more or less opaque in the living worm, cells, which appear 

 to be arranged in rather squarish lateral masses were observed, 

 beginning not far back of the ventral sucker. Behind these, and 

 between the laterally placed smaller bodies, kinks in the intestinal 

 rami, a lot of relatively large nucleated cells were observed. 



In both of the mounted specimens the mouth is terminal, the oral 

 sucker is longer than broad, and the ventral sucker is considerably 

 larger than the oral. There is no pharynx ; what was at first taken to 

 be a pharynx in one proved to be a kink in the esophagus. The 

 excretory pore is terminal. 



