174 PROCEEDINGS OF THE NATIONAL MUSEUM vol.84 



The ducts are short with thick muscular walls and longitudinal folds 

 in the inner lining. A diverticular chamber with irregularly folded 

 lining is buried in the anterior wall of each duct and its cavity is 

 connected with the lumen of thespermathecal duct by a small channel. 

 A comparison of the data in the foregoing descriptions seems to 

 the writer to justify the recognition of the two new species M. 

 cascadensis and M. maceJfreshi, of each of which only a single speci- 

 me^ is available. The much greater number of somites, the paired 

 papillae of the somites anterior to the clitellum, the much simpler 

 type of calciferous gland development, and the location of the com- 

 munication of the sperm ducts with the prostate glands would pre- 

 clude the inclusion of either of them with either of the other new 

 species. They differ from 31. amencanus in having paired papillae 

 anterior to the clitellum, having the sperm ducts of either side re- 

 maining separate until they reach the prostate gland, in the character 

 of the penial setae, and in the extent of the clitellum. They differ 

 from each other in the marked difference in the spacing of the 

 setae, which is much greater than one would expect to find between 

 two specimens of the same species. There are also differences of 

 less importance in the lengths of the penial setae and the number of 

 papillae anterior to the clitellum. 



Genus PLUTELLUS E. Perrier 



Plutellus Pebbieb, Arch. Zool. Exp. et Gen., vol. 2, p. 250, 1873. 



The majority of the large number of species of the genus PluteUus 

 already described are from the Australian region. Although the 

 description of P. heteroporus., on which the genus was founded by 

 Perrier in 1873, was based on two specimens collected in Pennsyl- 

 vania, no other specimens of this species have yet been reported, nor 

 have other species of the genus been found in the eastern part of 

 the United States. Benham (1892) described a species, P. perrierf, 

 based on two specimens collected on the Queen Charlotte Islands, 

 British Columbia. Eisen described a genus, Argilophilus., to which 

 he assigned three species found in California and one in Guatemala 

 but which are now assigned to PluteUus (Eisen, 1894 and 1900). 

 Michaelsen (1921) described P. sierrae from California. 



The species of Plutellus here described from Oregon are associated 

 with species of Megascolkles, and representatives of both of these 

 genera are also found in Australia, Tasmania, and India. 



Important characters of the genus PluteUus as given by Stephen- 

 son (1930, p. 833) are: "Setae eight per segment. Male pores paired 

 or single; female pores mostly paired; spermathecal pores end at 

 furrow 8/9 or on segment ix, a single pair, or a series of two to five 



