190 
Bemidgi, Minnesota, Sept. 8, 1911 contained a number of these para- 
sites in the intestines. The worms were collected by Hermann Douthitt 
who kindly gave some of them to the writer. 
In his key to the Acanthocephala Lühe (1911) recognizes but a 
single species of Neorhynchus, N. rutili (O. F. Müller), as occurring in 
central Europe. Consequently his key which is purely an artificial 
device for use in connection with forms within the scope of his work 
succeeds only in setting off this one form from the other Acanthocephala 
under consideration. At the beginning of this paper I have given a 
diagnosis of the characters of the genus Neorhynchus. In the following 
key to the species only American forms have been considered. Failure 
to include the European species in this key is due to the fact that con- 
siderable confusion exists as to the absolute identification of the two 
described species which the writer hopes to make clear in a later paper. 
In so far as possible only purely diagnostic points have been introduced 
into this key. 
1) [8] Proboscis with three circles of hooks . - - - 222 
2) [3] Twelve hooks in a circle . Neorhynchus gracilisentis n. sp. 
3)) j2] Sixhooks in à circle N ade ai 
4) [7] Terminal hooks over 0,090 mm. lone ER IR hee 
5) [6] Basal hooks over 0,030 mm. long (0,035 —0 054 mm.) 
Embryos 0,016 0,011 mm. 
Body 8—32 mm. long. . . Neorhynchus emydis (Leidy) 
6) [5) Basal hooks under 0,030 mm. long 
Body 2—5 mm. long . . . Neorhynchus tenellus n. sp. 
7) [4] Terminal hooks under 0,090 mm. long 
Basal hooks 0,020—0,025 mm. long 
Embryos 0,049—0,051 mm.  0,015—0,021 mm. 
Body 4—15 mm. long. . Neorhynchus cylindratus n. sp. 
8) [1] Proboscis long, armed with numerous hooks in irregular 
circles of usually about six hooks each 
Neorhynchus longirostris n. sp. 
Literature cited. 
Hamann, Otto, 1892, Das System der Acanthocephalen. Zool. Anz. 15. S. 195. 
Kaiser, J. E., 1913, Die Acanthocephala und ihre Entwicklung. Beitrage zur 
Kenntnis der Histologie, Ontogenie und Biologie einiger einheimischer 
Echinorhynchen. Leipzig. S. 66. 2 Taf. 
Leidy, Joseph, 1852, Contributions to Helminthology. Proc. Acad. Sci. Phila- 
delphia. 5. p. 205—209. 
——, 1857. A Synopsis of Entozoa and Some of their Ectocongeners observed by 
the author. Proc. Acad. Sci. Philadelphia. 8. p. 42—58. 
Lühe, Max, 1911, Die SüBwasserfauna Deutschlands. Heft 16. Acanthocephalen, 
Jena. 116 S. 87 Figuren. 
