ACANTHOCEPHALA jq 



Arhythmorhynchus teres, new species. 



Body of preserved specimen about 43 mm. long with a diameter of 0,75 

 mm. near anterior extremity. Remainder of body varying somewhat in dia- 

 meter in different regions but about 0,3 mm. broad. Posterior region swollen 

 to a diameter of about 0,68 mm. and bluntly truncated at termination. Pro- 

 boscis 0,77 mm. long, slightly ditated (0,325 mm. across) at the middle and 

 of smaller diameter (0,33 mm.) at tip and base. Proboscis hooks in 18 longi- 

 tudinal rows of about 14 to 16 hooks each. Hooks not differing much in 

 length but in different parts of proboscis varying widely in contour and in 

 thickness, usually about 60 [i long; those near base very slightly curved and 

 delicate, while those near the middle of proboscis in some instances have a 

 diameter of 18 [j. at the point of emergence from proboscis wall. 



Habitat: intestine of Lams doniinicanus at Talcahuano, Chile. Collected 

 November 22, 1916 by Mr. K. BACKSTROM. 



Type deposited in the Riksmuseum in Stockholm. 



Literature Cited. 



LuHE, M., 191 1. Acanthocephalen. Die Siisswasserfauna Deutschlands, Heft 16. Jena. 



, 1912. Zur Kenntnis der Acanthocephalen. Zool. Jahrb., Jena, Suppl. 15, 



Bd. i: 271 — 306. 



Neveu-Lemaire, M., 1905. Sur les Parasites des Poissons du Genre Orestias. Bull. 

 See. Philomathique de Paris, 'I'ome 7: 255 — 259. 



Van Cle.we, H. J., 1918. Acanthocephala of the subfamily Rhadinorhynchinae 

 from American fish. Jour. Parasitol., 5: 17 — 24. 



, 1920. Two new genera and species of Acanthocephalous worms from Vene- 

 zuelan fishes. Proc. U. S. Natl. Museum, 58: 455 — 466. 



