82 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 50. 



terior of the anus. The eggs are 110 to 142 /u, long by 30 to 40 [m thick. 

 The embryo is not formed at the time of oviposition. 



Hosts. — Mus musculus, Mus musculus alhus, Micromys minutus 

 {Mus minutus) , Apodemus sylvaticus {Mus sylvaticus) , Epimys rat- 



tus {Mus rattus), Epimys ugan- 

 dae {Mus ugandae), Mus muscu- 

 lokles^ Microtus arvalis {Arvi- 

 cola campestris.^ Lemmus ar- 

 valis, Arvicola arvalis), Evo- 

 tomys glareolus {Arvicola 

 glareolus, Arvicola ruhidus), 

 Pitymys suhterraneus {Arvicola 

 subterraneus) , Arricola amphih- 

 ius {Lemmus amphihius), Evo- 

 tomys rutilis {Lemmus rutilis), 

 Onychomys leucogaster {Ilesperomysleucog aster), II olochilus physo- 

 des {Ilesperomys p}iysodes),Peromyscus nasutus {Ilesperomys nasu- 

 tus), Oxymycterus nasutus, Citellus citellus {Spermophilus citellus, 

 Arctomys citellus), Ilolochilus hrasiliensis {Ilolochilomys brasilien- 

 sis), Mus minutoides {Leggada minutoides), Neotoma mexicana 

 fallax, Arvicanthis harbarus. 



Fig. 95.— Oxyuris obvelata. Posterior ex- 

 tremity OF MALE. Enlarged. After von 

 LlNSTOW, 1879. 



FlQ. 96.— OXYXJRIS OBVELATA. POSTERIOR EXTREMITY OF FEMALE, SUOWING FUNGUS GROWTH. EN- 

 LARGED. After von Linstow, 1S84. 



Location. — Cecum and large intestine. 



Localities. — Cosmopolitan: France (Rennes), Germany (Oreifs- 

 wald), Austria (Vienna), Australia (Brisbane), Africa (Fort Portal, 

 Kitagueta), United States (Washington, District of Columbia; 

 Bowie, Maryland; Colorado Springs and San Acacia, Colorado). 



For the most part this species has been considerably confused with 

 Oxyuris tetraptcra. In his original description Ivudolphi has con- 

 fused the two forms. This is not surprising, in that the two occur 

 in the same location in the same hosts and are much the same in 



