44 THE SHORTER SCIENTIFIC PAPERS 



removed P. breviseta to the genus Naidium which thus 

 consisted of two species, N. luteum and N. breviseta. 



The characters which may be used for separating the 

 two genera consist of (1) the presence as a rule of bi- 

 uncinate setas in the dorsal bundle of Naidium, while such 

 setae are absent in Pristina, and (2) the development of 

 the tentacular process of the prostomium which is either 

 absent or extremely short in Naidium while in Pristina it 

 is long. The absence of any tentacular process in N. 

 osborni suggests that until a species is found in which the 

 process is well developed and in which the dorsal bundles 

 contain biuncinate setse, the genera may be considered 

 distinct. Further studies may show other generic 

 characters. 



I take pleasure in dedicating this species to Professor 

 Herbert Osborn, Director of the Lake Laboratory, 

 Sandusky, Ohio. 



BIBLIOGRAPHY 



Only a few of the more important papers, particularly those referring to North 

 American Naidida:, are noted. 

 Beddard, F. E. 



'95. A Monograph of the Order of Oligochasta. Oxford. 

 Bretscher, K. 



:00a. Mitteilungen ueber die Oligochastenfauna der Schweiz. Rev. Suisse Zool., 

 vol. 8, pp. 1-44. 

 Bretscher, K. 



.•00b. Siidschweizerische Oligochxten. Rev. Suisse Zool., vol. 8. 

 Bretscher, K. 



:03. Beobachtungen ueber die Oligochasten der Schweiz, VII. Rev. Suisse Zool., 

 pp. 1-21. 



Cragin, F. W. 



'87. First Contributions to a Knowledge of the Lower Invertebrata of Kansas. 

 Bull. Washb. College Laboratory, vol. 2, no. 8, pp. 27-32. 

 Leidy, J. 



'JOa. Description of New Genera of Vermes. Proc. Acad. Nat. Sci. Philadel- 

 phia, pp. 124-126. 

 LEroY, J. 



'job. Descriptions of some American Annelida Abranchiata. Journ. Acad. Nat. 

 Sci. Philadelphia, vol. 2, pp. 43-55. 

 LErov, J. 



'52a. Helminthological Contributions. Proc. Acad. Nat. Sci. Philadelphia, vol. 

 5, pp. 226-227. 

 Leidy, J. 



'52b. Corrections and Additions to Former Papers on Helminthology. Proc. 

 Acad. Nat. Sci. Philadelphia, vol. 5, pp. 285-287. 



