RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY. 219 

 [July, 1888. No 569. See Bibliography.] 



PARASITES OF THE SHAD AND HERRING. * 



With the view of ascertaining the parasites of the shad, Alosa 

 sapidissima , I examined the entrails of fifty fish brought to our mar- 

 ket from the rivers of the south and from the Delaware. Most of 

 them were found to be infested with two nematoid worms, the Aga- 

 monerna capsularia, Diesing, and the Ascaris adunca, Rudolphi, and 

 all of them with the larva or scolex of a cestoid worm, which I pro- 

 pose to distinguish as Gynuioscolex pida. I also examined half a 

 dozen of the closely allied fish, the common herring, Clupea hare?i- 

 gus, in which I also found the Agamonema capsularia and Gymno- 

 scolex pida, but not the Ascaris adiinca. 



Agamonema capstdaiia, Diesing. — This worm, knowm only in the 

 immature sexual condition, is a frequent and common parasite of 

 many fishes. Called by Linnaeus the Gordius marinus, it has been 

 described under various other names by different authors. Observed 

 in Europe as a parasite of the herring, it has also been there noticed 

 in the salmon, mackerel, cod, turbot, halibut, and other fishes. In 

 our herring it appears to be a constant parasite, sometimes few and 

 often in considerable numbers. It occupies the abdominal cavity 

 among the viscera usually encysted in the peritoneum about the 

 stomach and intestine, and especially the pyloric appendages, and less 

 frequently on the liver and roes. It often forms flat and close spiral 

 coils, lying on the viscera or appended to them. Frequently it is ob- 

 served free and incessantly wriggling ; but in this condition I suspect 

 the worm has escaped from its cyst after the death of the herring. 



The Agamonema is also a common parasite of the Shad, and 

 though usually occurring in small numbers, appears to be as constant 

 as in the Herring. Mostly, too, it is larger than in the latter, and is 

 found in the same positions and conditions. It is most frequently 

 observed in conspicuous coils, appended to the viscera, and especially 

 to the coecal extremity of the stomach. It was found in every Shad 

 examined, from three to a dozen or more. 



The characters of the Agamonema of the Herring were as follows : 

 Body slender, most tapering in advance, translucent white, and often 

 with the intestines browaiish, but in others w^hite. Head rounded, 

 truncate and bordered by conical papillae, with the mouth unarmed, 

 but furnished to one side wnth a minute conical spine attached by a 

 broad base. Tail short, conical, incurved, blunt, but terminating in 

 a minute mucro. 



* Journal of Comparative Medicine and Surgery. 



