HELMINTH PARASITES OF BIRDS — DENTON AND BYRD 159 



at a level approximately midway between acetabulum and posterior 

 end of body. Vitelline ducts emerging from yolk glands at a level 

 one-third to one-half their length from anterior limits, uniting in 

 median plane of body to form common vitelline duct. Uterus greatly 

 convoluted, filling most of body behind ovary, passing anteriorly on 

 right or left side of ovary and posterior testis, between testes, dorsal 

 to acetabulum and cirrus sac, terminating in a weakly muscular metra- 

 term. Metraterm equal in length in cirrus sac. Ova numerous, dark 

 brown when mature, measuring 26ju, to 33ju, long by 18ju, to 22ju, wide. 

 Ciliated miracidium possessing a stylet and two large oval, oppositely 

 situated vesicles which are filled with refractile granules. 



Additional hosts. — Toxostoma rufum (Linnaeus) and CyaTWcitta 

 cristata (Linnaeus). 



Habitat. — Liver and gall bladder. 



Localities. — Georgia : Augusta and Athens ; Mississippi : State Col- 

 lege ; Texas : Houston and Eagle Lake. 



il/ai^enaZ.— Specimens No. 36749, 36750, 36751, and 36794 have been 

 deposited in the helminthological collection of the United States 

 National Museum. 



Remarks. — Lyperosomum oswaldoi is described here from numerous 

 specimens from the liver and gall bladder of the brown thrasher, 

 Toxostoma rufum., and two specimens from the gall bladder of the 

 blue jay, Cyanocitta cnstata.^ from the southern United States. The 

 parasite is common in the brown thrasher, being recorded from 20 

 (48.8 percent) of 41 specimens of this species examined to date. The 

 blue jay, on the other hand, must be considered as a rare or accidental 

 host for the species, since only a single specimen (3.8 percent) of 26 

 birds proved to carry the form in its gall bladder. However, the 

 parasite in the blue jay was normal in every way and was fully gravid. 

 The specimens from tlie blue jay were indistinguishable from those 

 in the brown thrasher. 



Lyyerosonruwrn oswaldoi apparently represents the New World 

 counterpart of L. longicauda (Rudolphi, 1809), from birds of the Old 

 World. In Europe L. longicauda appeal^ to be confined to birds of 

 the family Corvidae (crows and jays), while L. oswaldoi has been 

 recorded from birds of the families Thraupidae (tanagers), Icteridae 

 (blackbirds), Phasianidae (partridges), and Fringillidae (sparrows) 

 in South America and from species of Mimidae (thrashers) and Cor- 

 vidae in North America (present paper). The two species, L. longi- 

 cauda and L. oswaldoi., have the same general body appearance and 

 internal organization but show certain minor differences. The body 

 and internal organs, with the exception of the ova which are consider- 

 ably larger, are smaller in L. oswaldoi than in L. longicauda. Very 

 probably L. oswaldoi will fall as a synonym of L. longicauda {sensu 



