70 



Part Hi. — T went 1 1 -eighth Annual Repori 



and lateral. The posterior suckers, which are small and of an oval form, 

 are each armed with four hooks, and each sucker appears to be divided into 

 two nearly equal parts. The suckers seem to be supported on minute 

 prominences and crowded together along the edge of the expanded 

 membranous border which terminates the posterior end of the body. 

 The number of suckers on the specimen represented by the drawing (fig. 6) 

 is fifty-two. According to van Beneden, the suckers are mobile and can 

 turn towards or away from each other, and that also by contraction to 

 appear sometimes to be fewer in number and sometimes more numerous. 

 Along the middle of the body and at the posterior extremity the colour 

 is yellowish-white, while along each side is a dusky-coloured border. 



The length of the specimen figured is about 10 mm., but others reach only 

 to 8 or 9 mm., or are even smaller. 



Habitat. — Parasitic on the gills of the sea pike or Gar-fish, Ramphistoma 

 belones, Linn. {Belones vulgaris, Cuv.) ; captured in the North Sea about the 

 end of x\pril and beginning of May, 1910: apparently not very rare. 



Genus Amphiptyches, Grube and Wagener (1852). 

 Amphiptyches urna, Grube and Wagener. PI. VIII. 



1852. Amphiptyches urna, G. and W., Muller's Archiv (1852). 

 PI. xiv. 



Several examples, which include some apparently adult as well as others 

 scarcely mature, were obtained in the intestine of specimens of Chimera 

 monstrosa sent to the Laboratory at the Bay of Nigg from the Aberdeen 

 Fish Market in January, 1910. The fish, it is understood, were captured in 

 the North Sea. 



Amphiptyches differs remarkably in its general appearance from the 

 Entozoa usually met with in the intestines of marine fishes, while on the 

 other hand it has a strong superficial resemblance to certain species of 

 the Nudibranch mollusca. There also appears to have been at first some 

 doubt as to the relationship between these parasites and the fish in which 

 they were observed. 



The parasite was described by Grube and Wagener in 1852 in Muller's 

 Archiv, under the name of Amphiptiches urna. The specimens, along with 

 the shells of Mactra — a Lamellibranch shellfish — were found in the intestine 

 of Chimera monstrosa captured in the Mediterranean. 



Diesing, in his Revision der Helminthen, 1858, ascribes this organism to 

 his genus Gyrocotyle, and records it under the name of Gyrocotyle 

 amphiptyches, Gr. and W. 



In 1859 Dr. Paul Gervais and P. -J. van Beneden. in their work "Zoologie 

 medicale," vol. ii., p. 193, after referring, under the sub-order Polycotylares 

 Blainv., to various genera of the Tristomidae, proceed to remark that the 

 g. Amphiptyches found by Grube and Wagener in the intestinal canal of 

 Chimera appeared to be a parasite of that mollusc, and that its position in 

 the fish was that of an erratic — a parasite that had lost its way by being 

 accidentally swallowed by the Chimera* 



In a further note, however, on these parasites published in his work on 

 "Les Poissons des Cotes de Belgique" in 1870, Professor P. -J. van Beneden 

 remarks that, having studied this singular worm only from specimens pre- 

 served in liquer obligingly communicated to him by G. Wagener, he had 

 some doubt about them being internal parasites of fishes, and adds that, 

 having since 1 procured an adult Chimera captured on the coast of Norway, 



* Le G. Amphiptyches, trouve par Grube et G. Wagener dans le canal intestinal de 

 la Chimere avec des coquilles de Mactre, pourrait bien etre un parasite de ce dernier 

 Mollusque, se trouvant a l'etat erratique dans le poisson qui l'a fourni. II n'y a en 

 efFet aucun autre ver polycotylaire vivant dans le tube digestif. 



