STOP Early Journal Content on JSTOR, Free to Anyone in the World This article is one of nearly 500,000 scholarly works digitized and made freely available to everyone in the world by JSTOR. Known as the Early Journal Content, this set of works include research articles, news, letters, and other writings published in more than 200 of the oldest leading academic journals. The works date from the mid-seventeenth to the early twentieth centuries. We encourage people to read and share the Early Journal Content openly and to tell others that this resource exists. People may post this content online or redistribute in any way for non-commercial purposes. Read more about Early Journal Content at http://about.jstor.org/participate-jstor/individuals/early- journal-content . JSTOR is a digital library of academic journals, books, and primary source objects. JSTOR helps people discover, use, and build upon a wide range of content through a powerful research and teaching platform, and preserves this content for future generations. JSTOR is part of ITHAKA, a not-for-profit organization that also includes Ithaka S+R and Portico. For more information about JSTOR, please contact firstname.lastname@example.org. EORHYNCHUS: A PROPOSED NEW NAME FOR NEO- RHYNCHUS HAMANN PREOCCUPIED* H. J. Van Cleave The genus Neorhynchus was founded in 1892 by Hamann to include Echinorhynchus rutili Muller and Echinorhynchus agilis Rudolphi. Practically all investigators dealing with the Acanthocephala since that date have accepted this generic name. Recently attention has been called to the fact that the name Neorhynchus is preoccupied. Sclater, in 1869, and, again, Milne Edwards, in 1879, employed it for other groups. In accordance with the laws of nomenclature, it then becomes necessary to reject the name Neorhynchus as applied to Hamann's genus. I propose the name Eorhynchus to designate these forms. While all other investigators dealing with this genus have been limited to a study of the two original species, it has been my good fortune to include five additional species in a comparative study, the results of which have led me to a restatement of its essential characteristics. As pointed out in an earlier paper (1913), I consider the following points as diagnostic for this genus of Acanthocephala: 1. Six giant nuclei in the subcuticula arranged, normally, five in the middorsal line of the body and one in the midventral line. 2. Two giant nuclei in one lemniscus and only one in the other. 3. Proboscis receptacle with but a single muscle layer in its wall. In the light of this analysis, the contentions of de Marval (1904: 582) and of Monticelli (1905:217), that Apororhynchus hemignathi Shipley should be included in this genus are based on an inadequate understanding of its natural limits. Shipley, in his description of A. hemignathi (1896:210), wrote: "As in Neorhynchus, the number of nuclei is very small, some twelve to twenty seem to suffice for the whole subcuticle, and perhaps two to four for each lemniscus. The nuclei are scattered about in a most irregular fashion. . . ." I have shown (1913) that not alone the presence of giant nuclei, but more strikingly their number and arrangement furnish a sure criterion for the determination of members of this genus. Shipley's genus Apororhynchus, because of its radical departure from the typical struc- ture of the Eorhynchi, cannot be included within the genus Eorhyn- chus. The valid species of this genus are, then, Eo. rutili (Muller * Contributions from the Zoological Laboratory of the University of Illinois, under the direction of Henry B. Ward, No. 32. VAN CLEAVE— EORHYNCHUS 51 1784), Eo. agilis (Rudolphi 1819), Eo. emydis (Leidy 1852), Eo. gracilisentis (Van Cleave 1913), Eo. longirostris (Van Cleave 1913), Eo. cylindratus (Van Cleave 1913) and Eo. tenellus (Van Cleave 1913). Hamann (1892) also created the family Neorhynchidae for the single genus Neorhynchus. Porta ( 1907 : 409) accepted Hamann's revision of the Acanthocephala only in part, recognizing but two families, Echinorhynchidae and Gigantorhynchidae, and included Neo- rhynchus under the former. The characteristics already listed as diag- nostic for the genus Eorhynchus, together with the complete fusion of the cement glands, are such essential features that the inclusion of Eorhynchus in the same family with Echinorhynchus would so distort our conception of the family Echinorhynchidae that it would cease to be a natural division of the Acanthocephala, and would become a purely artificial assemblage. In view of these facts I consider that the evidence fully justifies the retention of the family rank originally attributed to these forms for which the family name now becomes Eorhynchidae. The writer's extensive studies on the cytology of the Eorhynchidae furnish conclusive evidence in support of the foregoing arguments. These studies in detail appear in the June number of the Journal of Morphology. REFERENCES Hamann, O. 1892. Das System der Acanthocephalen. Zool. Anz., 15: 195. de Marval, L. 1904. Sur les acanthocephales d'oiseaux. Note preliminaire, Rev. suisse de zool., 12 : 573-583. Monticelli, F. S. 1905. Per una rettifica. A proposito di una proposta classificazione degli Acantocefali. Boll. Soc. Natural. Napoli, 19: 217-218. Porta, A. 1907. Contributo alio studio degli Acantocefali dei Pesci. Bio- logica Torino, 1:377-423. Shipley, A. E. 1896. On Arhynchus hemignathi, a new genus of Acantho- cephala. Quart. Jour. Micr. Sci., 39: 207-218. Van Cleave, H. J. 1913. The Genus Neorhynchus in North America. Zool. Anz., 43: 177-190.