152 BULLETIN 140, UNITED STATES NATIONAL MUSEUM 



CONTRACAECUM MICROCEPHALIA (Rudolphi, 1809) Baylis, 1920b 



Synonyms. — Asca?is microcephala Rudolphi, 1809 ; Kathleena arc- 

 uata Gedoelst, 1916; C ontracaecum quadricuspe Walton, 1923. 



Baylis and Daubney have examined the type specimens of Kath- 

 leen® arcuata and find that species identical with Rudolphi's. The 

 present writer considers C. quadricuspe identical also, the descrip- 

 tion given by Walton agreeing closely with that of Gedoelst in all 

 particulars except that the esophageal appendix of G. quadricuspe 

 is somewhat shorter and the vulva slightly more anterior. 



Hosts. — Anas boschas, Anas domestica, Ardea cinerea, A. cornata, 

 A. herodias, A. minor, A. nycticorax, A. purpurea, A. species, A. 

 stettaris, Ardeolo grayi, A. rattoides, Botauras mugitans, B. stel- 

 laris, Butorides virescens virescens, Ciconia alba, C . nigra, Herodias 



Fig. 222. — Contracaecdm microcethalom. a, Front view of head ; 6, dorsal 

 view of head ; c, male tail ; d, free end of spicule ; e, cross section of spicule. 

 After Gedoelst, 1916 



egretta, H. tricolor, Nyctiardea grlsea, Nycticorax europaeus. N. 

 nyctieorase. 



Location. — Proventriculus and intestine. 



Morphology. — C ontracaecum (p. 146) : Color yellow-white. Cuticle 

 cross-striated; directly behind the head the furrows thus produced 

 are so deep that a shirred appearance results. Mouth with 3 lips and 

 3 interlabia, all with thick transparent cuticle. Lips equal, on their 

 internal surface a longitudinal furrow; ear-shaped projections 

 anteriorly. Dorsal lip (fig. 222&) with 2 large double papillae, the 

 ventro-lateral lips each with 1 large double papilla. Interlabia of 

 about the same height as the lips, with a free curved internal part 

 which is incised at its summit. No lateral alae. Cervical papillae 

 400 to 720/* from head end. According to Gedoelst's description 

 (K. arcuata) , esophagus 2.8 to 3.2 mm. long by 160 to 225/a wide, with 

 an appendix 1.1 to 1.25 mm. long by 145/x wide; cecum extends 

 anteriorly along esophagus for 3/4 the latter's length. According to 



