494 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 85 



rather unusual variation in the setal numbers are also to be explained 

 as the result of parasitic infection. 



So many of the specimens are parasitized or show evidence of 

 previous infestation or are abnormal that the determination of the 

 normal range of variation of important characteristics has not been 

 poFsible. Whenever normal specimens are available the variation in 

 the setal numbers and the location and numbers of the genital mark- 

 ings should be recorded. 



The male parietal invaginations of P. tschiliensis are very similar 

 to those of P. praepinguw. The two species are distinguished from 

 each other by characteristics of structures at the ectal end of the 

 spermathecal ducts. There is evidence to indicate that the develop- 

 ment of the spermathecal apparatus may be affected in various ways 

 as the result of the presence in the worms of large numbers of para- 

 sites. If the parasitic influence is able to inhibit the development of 

 the spermathecal pore invaginations in P. praepinguis^ such abnormal 

 specimens may be very difficult to distinguish from P. tschiliensis. 



Specimens of P. tihetana {= P. tschiliensis) were originally re- 

 garded as conspecific with the Tientsin specimens of P. asiatica 

 (Michaelsen, 1903, p. 11). The distinctions that Michaelsen later 

 made between P. asiatica and P. tihetana do not appear to be of 

 importance. 



Specimens of P. asiatica have not been available for examination. 

 The species is inadequately characterized. P. tihetana and P. asiatica 

 may be synonymous as Michaelsen originally thought, or asiatica 

 may be a synonym of P. guillelmi. 



PHERETIMA TUBERCULATA Gates 



1935. Pherethna tuherculata Gates, Smithsonian Misc. Coll., vol. 93, no. 3, 



p. 18 (type locality: Suifn, Szechwan; types in the U. S. National 

 Museum). 



1936. Pherctima tuhcrculatn Chen, Contr. Biol. Lab. Sci. Soc. China, zool. !ser., 



vol. 11, p. 302 (after examination of type). 



Material examined. — From Dr. Graham: 1 clitellate specimen la- 

 beled "Suifu, 1,000 feet, April-May 1925"; 1 partially clitellate speci- 

 men and 3 clitellate specimens labeled "Suifu, 1929"; 1 aclitellat© 

 specimen and 1 clitellate specimen labeled "Mupin, 3,500-,5,000 feet, 

 July 1, 1929." 



External characteristics. — Length, 80-110 nun. Diameter, 3-5 mm. 



The setae begin on ii, on which segment there is a complete circle. 

 A midventral gap in the setal circle is usually lacking, when present 

 slight; a middorsal gap also usually lacking, when present variable 

 though never very wide. The setal numbers are as follows* 



