4 PROCEEDINGS OF THE NATIONAL, MUSEUM vol.88 



Genus AMPHIBDELLA Chatin, 1874 



AMPHIBDELLA FLAVOLINEATA MacCallum 



AmpMMella flavoUneata MacCallum, Zoopathologica, vol. 1, No. 1, p. 29, 1916. 



On August 3, 1910, 16 trematodes were collected from the gills 

 of a torpedo (Tetranarce occidentalis) that had been taken in a fish 

 trap at Menemsha Bight. 



Color, white. Measurements, life: Length, 3.78 mm.; breadth, 

 maximum, about middle, 0.64 mm., in front of caudal disk 0.29 mm. ; 

 breadth of caudal disk, 0.42 mm. On July IT, 1911, we found 

 U.S.N.M. No. 8144, and again, on July 7, 1914, several were collected 

 from the gills of torpedoes. 



As Dr. MacCallum had taken up the study of the monogenetic 

 trematodes at Woods Hole in the summer of 1912, I made no further 

 collections from the gills of the torpedo, but on August 3, 1920, I 

 noted that they were numerous on the gills of one that was examined 

 on that date for parasites. The specimens collected correspond to 

 A. fiavolineata MacCallum. 



Family MONOCOTYLIDAE Taschenberg, 1879 



Subfamily Dionchinae Johnston and Tiegs, 1922 



Genus DIONCHUS Goto, 1899 



DIONCHUS AGASSIZI Goto 



Plate 14, Figubes 162, 163 



Dionchus agassizi Goto, Journ. Coll. Sci. Imp. Univ. Tokyo, vol. 12, pp. 286-291, 

 figs. 19-21, 1899. 



I have record of the finding of this trematode on the gills of 

 remora on three occasions. The anterior end is broadly sagittate, 

 with mouth at base of triangular head. In the living worm toothlike 

 processes are very indistinct. The body is of nearly uniform breadth 

 until near the posterior end, where it tapers to the posterior sucker. 

 The posterior sucking disk in this species is characterized by being 

 divided into 10 areas by as many radial ridges, which do not quite 

 reach the center of the disk. On account of the contracted condition 

 of the disk, and its position, showing only in lateral view in all but 

 one of the mounted specimens, its structure cannot be made out 

 satisfactorily. In the one specimen in which a ventral view of the 

 disk is shown, no radial ridges can be distinguished. The distal 

 ends of the two hooks on the disk of each of the mounted specimens 

 are broken off. They are described by Goto as being clawlike. He 



