NO. 14 MANTER : DIGENETIC TREMATODES OF FISHES 437 



pacificaj both species show at least one conspicuous loop of each crus in 

 the forebody. 



The two species occur in closely related hosts in the two oceans and 

 can be considered as examples of "twin species." 



The only other species in the genus Leurodera is L. decora Linton, 

 1910, common in Haemulon species at Tortugas, Florida. This species 

 has been studied by the writer and since some details of Linton's descrip- 

 tion are incorrect and no diagnosis for the genus has been given, the 

 following diagnosis of Leurodera is proposed. 



LEURODERA Linton, 1910 



Smooth-bodied hemiurids, without ecsoma, subfamily Derogeninae. 

 Acetabulum in or posterior to midbody. Genital pore near intestinal bi- 

 furcation. Testes symmetrical, far apart, largely extracecal. Sinus sac 

 ovoid, muscular, containing a muscular ductus hermaphroditicus and 

 genital atrium. Prostatic vesicle external ; seminal vesicle tubular. Ovary 

 median, posttesticular ; seminal receptacle present; vitellaria compact, 

 oblique, to right of ovary ; uterus extending a short distance posterior to 

 ovary but not posterior to posterior vitellarium ; eggs without filament. 

 Excretory vesicle forking posterior to acetabulum; the excretory crura 

 folded in loops anterior to acetabulum, uniting dorsal to oral sucker. 

 Type species: Leurodera decora Linton, 1910. 



Gonocercella pacifica, new genus, new species 

 (Plate49, fig. 128) 



Host: Trachinotus rhodopus (Gill) 



Location: Stomach 



Locality: Port Utria, Colombia 



Frequency : A single specimen from one of the hosts examined 



SPECIFIC DIAGNOSIS OF GONOCERCELLA PACIFICA 



Body cylindrical, thick skinned, smooth except for flexture wrinkles, 

 rounded at each end, tapering only slightly from the acetabular region, 

 ecsoma lacking. Acetabulum posterior to midbody. Total length of 

 body 3.604, of which 2.173 is forebody (anterior to acetabulum) ; great- 

 est width, at acetabular level, 0.972. Oral sucker subterminal, subspheri- 

 cal, slightly longer than wide, 0.405 in transverse diameter. A distinct 

 large papilla or small lobe projects on the ventral surface of the anterior 



