438 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



end immediately anterior to oral sucker. Acetabulum subspherical, 0,622 

 in diameter; sucker ratio approximately 2 :3. Pharynx close to oral sucker, 

 0.165 long and 0.150 wide; short esophagus bearing a rather long ovoid 

 ventral diverticulum; ceca extending rather close together to posterior 

 end of the body where they do not unite. Genital pore median, a short 

 distance posterior to intestinal bifurcation. A nipplelike genital papilla 

 can be seen within the genital atrium. It is actually the tip of a large 

 muscular genital cone measuring 0.119 in length and 0.093 at its broad 

 base. (This genital cone is similar to that found in Derogenes and re- 

 lated genera.) Prostatic vesicle very large, ovoid, 0.240 long and 0.180 

 wide, largely filling intercecal space at that level, surrounded by a few 

 prostatic cells and serving as both prostatic vesicle and pars prostatica; 

 seminal vesicle a coiled tube overlapping posterior part of prostatic vesi- 

 cle, extending only a short distance posterior to it. It makes one diagonal 

 hairpin loop and is bent sharply at each end. The testes are large, imme- 

 diately postacetabular, diagonal, in contact with one another, overlapping 

 at least one cecum. Ovary immediately posttesticular, somewhat wider 

 than long, unlobed, overlapping both ceca ventrally; vitellaria two small 

 compact masses, unlobed, immediately postovarian, side by side, overlap- 

 ping the ceca ventrally ; uterus not extending posterior to ovary, in short 

 more or less lateral coils, overlapping the ceca at first dorsally then ven- 

 trally; seminal receptacle apparently lacking; normal eggs not present in 

 type specimen, very thin-shelled eggs of extremely variable size present, 

 no filaments visible, probable usual size about 34 by 15 ix. Crura of ex- 

 cretory vesicle unite dorsal to pharynx. 



This trematode is unique especially in the male terminal genital or- 

 gans and seems to warrant a new genus of the family Hemiuridae, sub- 

 family Derogeninae. The following diagnosis is proposed. 



GENERIC DIAGNOSIS OF GONOCERCELLA 



Smooth bodied, cylindrical hemiurids of fairly large size, without ec- 

 soma; acetabulum posterior to midbody; ceca do not unite; genital pore 

 near or posterior to intestinal bifurcation; testes preovarian, postacetabu- 

 lar, diagonal, close together ; seminal vesicle a coiled tube far anterior to 

 acetabulum; prostatic vesicle very large, surrounded by prostatic cells; 

 genital cone large and muscular, projecting into a spacious genital atri- 

 um; ovary ovoid, posttesticular; vitellaria two unlobed masses, postovari- 

 an; seminal receptacle lacking; uterus not extending posterior to ovary. 

 Type species : Gonocercella pacifica. 



