194 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



terminating about midway between acetabulum and posterior end of 

 body. Vitelline ducts arising from middle of vitellaria. Uterus 

 greatly convoluted, filling most of postacetabular region of body, then 

 following an undulating course to genital pore. Ova numerous, dark 

 brown when mature, 30/x to 36/* long by 20jti to 24/x wide. 



Additional hosts. — Cyanocitta cristata (Linnaeus), Richmondena 

 caTdinalis (Linnaeus), Eedymeles ludovicianus (Linnaeus), and 

 Melanerpes erythroce'phalus (Linnaeus). 



Habitat. — Liver and gall bladder. 



Localities. Texas: Houston, Dewalt, and Eagle Lake; Missis- 

 sippi : State College ; Nebraska : Lincoln. 



Specimens No. 36734 from the blue jay Cyanocitta cristata.. No. 36735 

 from the red-headed woodpecker, Melanerpes erythrocephalus^ and 

 No. 36736 from the cardinal, Richmondena cardinalis, have been de- 

 posited in the helminthological collection of the United States 

 National Museum. 



The above description of Zonorchis petiolatmn is based on a study 

 of more than 100 living and preserved specimens. Usually the num- 

 ber of worms per host is small, but as many as 75 specimens have been 

 taken from a single blue jay from the vicinity of Houston, Tex. In 

 this locality this trematode seems to be particularly prevalent in the 

 blue jay and cardinal. Numerous blue jays and cardinals examined 

 from other localities by the authors have not been found to be infected. 



Railliet (1900) very briefly described under the name of Dicrocoe- 

 lium petiolatum a trematode from the liver of Garrulus glandarius, 

 the European jay. The following year Braun (1901) obtained from 

 the same host a trematode that he identified as being identical with 

 that described by Kailliet. In the same paper Braun ( 1901) described 

 a second species, Dicrocoelium delectans, from the liver of Thrawpis 

 jjalmarttm., a South American tanager. Undoubtedly, the incomplete- 

 ness of Eailliet's description of D. petiolatmn., together with the fact 

 that certain discrepancies between length of body, ratio of sucker 

 sizes, and egg size in the material studied by Braun from the Euro- 

 pean jay on the one hand, and from the South American tanager on 

 the other, led Braun to redescribe and illustrate these two forms as 

 separate and distinct species in a subsequent paper published in 1902. 

 In this latter paper Braun gave a more complete description of the 

 two forms and materially modified the discrepancies between the two 

 forms as relating to ratio of suckers and size of the egg, thereby bring- 

 ing these two forms into closer agreement. Braun, however, retained 

 both forms as separate species. 



Nicoll (1915) transferred Dicrocoelium petiolatmn to the genus 

 Platynosomum Looss, 1907, while Travassos (1916) considered D. 

 delectans a member of this same genus. In 1944 Travassos trans- 

 ferred D. petiolatwn to the genus Lyperosonvum Looss, 1899. 



