NO. 14 MANTER : DIGENETIC TREMATODES OF FISHES 383 



Although only a single specimen was collected from the Galapagos 

 Islands, it is in good condition and shows all the specific characters to be 

 identical with the Atlantic species. For example, not only are all the or- 

 gans identical in position, shape, and size, but the eggs are identical in 

 size and shape and possess the characteristic tubercle at one pole. There 

 seems no doubt as to the identification of the parasite. 



There may be some doubt whether H. oscitans should be retained in 

 the genus Hamacreadium. The median genital pore and the form and po- 

 sition of the testes and ovary would so indicate, but the vitellaria do not 

 extend anterior to the acetabulum, and the excretory vesicle reaches only 

 to the posterior fourth of the acetabulum. While Yamaguti (1934) con- 

 siders the extension of the excretory vesicle anterior to the acetabulum a 

 generic character, McCoy (1930) found it did not reach beyond the 

 acetabulum in H. gullela. For the present, H. oscitans is retained in the 

 genus Hamacreadium. 



Podocotyle mecopera, new species 

 (Plate40, fig. 65) 



Host: Unidentified, spotted grouper 

 Location : Intestine 

 Locality: James Island, Galapagos 

 Number : 9 specimens from one host 



This trematode fits the rather broad generic diagnosis of Podocotyle 

 as given by Park (1937) except that the vitellaria do not reach to the 

 region of the acetabulum. Another uncommon Podocotyle feature is the 

 unlobed ovary. The species is, however, considered in the genus Podo- 

 cotyle. 



SPECIFIC DIAGNOSIS OF PODOCOTYLE MECOPERA 



Body elongate, little flattened, subcylindrical, tapering toward each 

 end, widest opposite acetabulum; length 1.849 to 2.538; width 0.517 to 

 0.600. Forebody short but usually contracted, 0.262 to 0.375 or Vq to 

 almost i/4o body length. Diameter oral sucker 0.157 to 0.188; acetabu- 

 lum wider than long; transverse diameter 0.375 to 0.420, slightly more 

 than twice diameter of oral sucker. Pharynx 0.102 to 0.144 long by 0.070 

 to 0.083; esophagus shorter than pharynx; bifurcation just anterior to 

 acetabulum ; ceca ending blindly near posterior end of body. Genital pore 

 well to the left, opposite intestinal bifurcation. Testes large, rounded, 

 smooth, tandem, close together but not quite touching, anterior testis 



