A NEW NEMATODE FROM THE RAT, AND ITS LIFE 



HISTORY 



By Eloise B. Cram 



Of the Zoological Division, Bureau of Animal Industry, United States 

 Department of Agriculture 



Through the courtesy of the superintendent of the National Zoo- 

 logical Park, Washington, D. C, there were turned over to the 

 present writer about 20 wild rats {Raftus iiorvegicus) which had 

 been killed in the Park. Upon postmortem examination the large 

 majority of the rats were found to harbor spirurid worms. The 

 nematodes were unusually large, and present in such numbers that 

 in many cases the stomach, esophagus, and upper end of intestine 

 were distended and densely packed with the w^orms. Upon exami- 

 nation the nematode proved to be a new species of Protospirura. 

 Several rats caught in another part of Washington (Department 

 of Agriculture buildings, about 5 miles from the Zoological Park) 

 failed to show the presence of these nematodes and the high percen- 

 tage of incidence in w'ild rats from the grounds of the Park there- 

 fore suggested that the rat was not the normal or original host but 

 had derived the infestation from some other rodent present in the 

 Zoological Park. The possibility that zoological gardens might act 

 as disseminators of parasites and that the rat might play an im- 

 portant role in that dissemination is worthy of consideration, and 

 it w^as thought by the present writer that a study of this nematode 

 and its life history might have practical as well as scientific interest. 

 Tlie description of the parasite and tlie experiincnts on its life 

 history are given below. 



PROTOSPIRURA COLUMBIANA, new spcc'os 



Specific diagnosis. — Frotosplrura: Large worms, the variations of 

 size of the adult worms, however, being unusually extensive. Cuticle 

 W'ith transverse striations and, in addition, thrown into loose folds, 

 the cuticle being so loose and distended in many of the worms as 

 to give the appearance of a larval cuticle about to be shed. Head 

 with 2 large trilobed lips. The lobes are of approximately equal 

 size, but the lateral lobes taper somewhat anteriorly, whereas the 2 



No. 2616.— Proceedings U. S. National Museum, Vol. 68. Art. 15. 



60731—25 



